The France international ended a nine-game scoring drought off the bench against Newcastle at the weekend and returned to the starting line-up in Piraeus to hit the winner in a 1-0 victory for the Gunners.
Lacazette had earlier been guilty of missing the best chance of the night, before he turned home Bukayo Saka’s cross with nine minutes remaining.
Beaten finalists last season, Arsenal will now have a lead to defend in the round-of-32 second leg at the Emirates Stadium in a week’s time as their defence once again stood tall.
For a side shipping chance after chance under previous coach Unai Emery, this was a third consecutive clean sheet for an Arsenal team clearly shaping up better at the back with Arteta at the helm.
The Spaniard had promised to name a strong side and made five alterations from the 4-0 victory at home to Newcastle four days earlier.
One of those decisions was to retain Bernd Leno as Arteta opted against switching his goalkeepers for this competition.
That soon paid dividends as the Germany international was forced into action inside three minutes, getting down low to push out Mathieu Valbuena’s effort.
Arsenal had started slowly and escaped another couple of decent chances for the hosts before they started to get a foothold in the game.
But Lacazette spurned a glorious chance, firing wide when well-placed in front of Jose Sa’s goal after good work from Joe Willock and Gabriel Martinelli fashioned the shooting opportunity.
Leno was again on his toes to keep out what would have been an unfortunate David Luiz own goal after the defender diverted a low cross at the first-choice stopper.
There were few opportunities for either side after the break as the rain continued to fall, Lacazette unable to get enough contact on a header from a Granit Xhaka cross as the Gunners searched for an away goal.
Arteta turned to Dani Ceballos and club-record signing Nicolas Pepe in the hope of leaving Greece with a victory, but it would be Lacazette, who had left his manager visibly frustrated on a number of occasions throughout the night, who would strike.
Pierre-Emerick Aubameyang had been shifted across the front line as Arteta sought a winning formula and he rolled in Saka down the left, with the teenager providing yet another assist as Lacazette got on the end of his low cross.
Lacazette missed another decent chance as Arsenal broke forward, Sa doing well to turn his shot behind before Shkodran Mustafi hit the crossbar with a header from the resulting corner.
One goal would have to suffice for Arteta and his players, but it was a hard-fought win which they hope will be enough to see them through in north London next week.
Jota hat-trick sinks Espanyol
Diogo Jota’s hat-trick and Ruben Neves’ thunderbolt kept Wolves’ Europa League dream alive after a dominant victory over Espanyol.
Forward Jota now has six goals in his last two European games after helping Wanderers to a 4-0 win over the LaLiga strugglers which puts them on the brink of reaching the last 16.
The hosts still lived dangerously in the first half when Rui Patricio denied Facundo Ferreyra after the goalkeeper’s error.
Ander Iturraspe escaped a first-half red card after clashing with Jota, but the visitors were well beaten in the first leg of their last-32 clash.
Boss Abelardo Fernandez made nine changes as Espanyol’s battle at the bottom of LaLiga appeared to take priority.
The Parakeets, who have won just four league matches this season, only briefly looked like threatening their superior hosts at Molineux.
The recalled Joao Moutinho fired over and Patricio was alert to get a hand on Lei Wu’s smart volley before Wolves took the lead after 15 minutes.
Jota scored a hat-trick in Wolves’ final group game, a 4-0 win over Besiktas, and he ended his eight-match drought with the opener.
The forward’s volley, after Raul Jimenez flicked on Moutinho’s short corner, clipped Victor Sanchez and nestled in the corner for his first goal since his European treble.
Two minutes later Andres Prieto thwarted Adama Traore after he was sent through by Jimenez.
Wolves were relaxed, with their much-changed visitors offering little threat, but Patricio almost gifted Espanyol an equaliser after 32 minutes.
Jimenez’s attempted clearance looped into the area and, rather than catch, the goalkeeper elected to volley away only to twice miss his kick.
It presented Ferreyra with a golden chance, but Patricio recovered to make a smart low save from point-blank range.
Espanyol were then lucky to keep 10 men on the pitch just before the break when Iturraspe and Jota tangled before squaring up.
The Espanyol midfielder pushed his head into Jota’s but escaped with a yellow card, much to Molineux’s anger, after a VAR check.
Wu had Patricio scrambling when his free header dropped wide two minutes after the break, but Wolves began to move out of sight in the 52nd minute with Neves’ screamer.
Traore’s cross was headed away by Victor Gomez and collected by Neves who controlled it on his chest before unleashing a stunning 25-yard volley which flew past Prieto.
Nuno felt comfortable enough to withdraw Traore and Jota confirmed Wolves’ dominance by making it 3-0 with 23 minutes left.
Matt Doherty swapped passes with Leander Dendoncker to slip in Jota, who held off Gomez to drill in from an angle.
Pedro Neto almost made it 4-0 when his 30-yard rocket hit a post but Jota had the final say with nine minutes left.
The striker scored his ninth European goal of the season when he drilled in low from the edge of the box.
Rangers pull off stunning comeback
Ianis Hagi delighted both his watching father Gheorghe and the Ibrox faithful as his double sent Rangers to a breathless 3-2 Europa League comeback victory over Braga.
On a wild night in Glasgow, with the Ibrox pitch again in a terrible state, it appeared Gers were set to slip up as the Portuguese visitors grabbed a two-goal lead.
First Braga’s Brazilian skipper Fransergio tamed the conditions with a stunning long-range opener before on-loan Barcelona striker Abel Ruiz added a clinical second.
But Rangers refused to lie down as they hit back to preserve Steven Gerrard’s 15-game unbeaten home run in Europe as Light Blues boss and take a major step towards the last 16.
Hagi got the fightback started as he reduced the deficit before playing a part in Joe Aribo’s equaliser.
And the Romania insternational then had his dad – former Real Madrid and Barcelona great Gheorghe – cheering from his seat in the Ibrox directors’ box along with the rest of the jubilant Gers faithful as his late deflected free-kick crept into the net to seal a narrow victory.
However, Gerrard’s team will have to rely on-loan Hibernian striker Florian Kamberi to spearhead their attack in the second leg after Alfredo Morelos was booked, meaning he is ruled him out of next Wednesday’s trip to Portugal.
Braga were denied the traditional eve-of-match training session and were instead forced to put in their final preparations at Gers’ Hummel Training Centre on Wednesday as the hosts sought to protect a pitch still recovering from its Storm Dennis battering.
But while the hosts seemed to slip and slide with every step early on, the visitors simply glided over the muddy surface.
There were two early warnings as first Bruno Viana stuck the rebound off an Allan McGregor parry into the side-netting before Francisco Trincao – the £26million striker who will join Barcelona this summer – fizzed just wide.
Rangers were making life hard for themselves as they failed to keep hold of the greasy ball.
And when Glen Kamara gifted possession after 11 minutes, Braga’s response was merciless. Paulinho and Joao Palhinha regathered before working it the ball to Fransergio, whose sensational 30-yard strike seemed to ride the wind on its way into McGregor’s postage-stamp corner.
In between those chances, however, the hosts had spotted an obvious flaw in the Archbishops’ high-pressing defence.
Pushing up, they left themselves vulnerable to the ball over the top and nearly paid an early price as Ryan Kent came within a toenail of converting a Morelos ball. The home side continued to probe in behind.
Hagi twice sent Morelos scampering through on goal, once with a poked through ball before the second a lovely diagonal which fooled Galeno into swiping at fresh air. But on both occasions Rangers’ top-scorer found himself foiled by goalkeeper Matheus.
Ibrox held its breath as another swipe of Trincao’s left foot crept just wide six minutes before half-time.
And they let out an almighty groan as Morelos saw yellow for the barge on Bruno Viana that now sees him banned for his fourth game this year already.
Fransergio almost doubled Braga’s lead just after the break as another long-range beauty shook McGregor’s crossbar.
But there was more frustration for Morelos after 57 minutes as he somehow failed to convert Hagi’s cross from point-blank range.
That miss was compounded three minutes later as Braga pounced again. Trincao’s clever flick took Niko Katic out of the equation and Ruiz drove forwards, unleashing an explosive right-footed drive low past McGregor.
But it was Hagi who took on the responsibility of lifting a crowd that had fallen quiet.
He saw a deflected strike clawed away by Matheus but his next effort after 67 minutes was perfectly placed to beat the keeper as it clipped the inside of his left-hand post to send the volume levels soaring.
He then combined with Aribo after 75 minutes as the Nigeria midfielder wriggled past four defenders before slotting home the leveller at the near post.
But the roar that met that strike was nothing compared to the one that followed with eight minutes remaining as Hagi’s set-piece took a wicked bounce off the wall to wrong-foot Matheus and spark wild celebrations round Ibrox.