Not a big game player, they said, but Olivier Giroud netted his first Arsenal hat-trick to send the Gunners into the knockout rounds of the Champions League.

A first half header was followed by two efforts after the break, sending Arsenal through with a comfortable 3-0 win on a night when they had to score at least twice.

After a nervy start to the game saw Héctor Bellerín struggling and Laurent Koscielny called into action to clear dangerous situations. Wary of being caught on the break, Aaron Ramsey picked up a booking for a professional foul before the Gunners finally started to look more settled.

Theo Walcott and Joel Campbell swapped wings, and the Costa Rican responded almost instantly to deliver Arsenal’s first chance of the match. French midfielder Mathieu Flamini met Campbell’s cutback, but his deflected effort struck the bar.

With just under half an hour on the clock, Olivier Giroud delivered a strike to give Arsenal fans hope. Mesut Özil brilliantly struggled away from pressure to release Aaron Ramsey down the left wing. His cross was met by Giroud, and Arsenal – after Koscielny had made another big clearance – went into half-time with half the job done.

Moments into the second half hearts were in mouths again, as Giroud laid down holding his ankle after Arsenal had defended a corner. Picking himself up off the ground, Arsenal’s French striker doubled his and Arsenal’s tally for the evening. A looped ball from Özil found Joel Campbell, who superbly plucked it out of the air and showed some quick feet and coolness to lay Giroud through. He made no mistake, tucking the ball into the far corner.

Theo Walcott had a chance to make it 3-0 deflected before the inevitable Olympiacos response began. Heading out of the competition, the home side pushed the Gunners back.

An inch-perfect Per Mertesacker tackle denied Brown Ideye a clear sight of goal with just over an hour gone.

Once again, Mesut Özil was the man to inspire an Arsenal attack when the pressure was on. The ball fell to Nacho Monreal at the back post, and his shot was blocked by the arm of Olympiacos right-back Omar Elabdellaoui. Giroud stepped up and scored. His first Arsenal hat-trick.

Mission accomplished. Arsenal are through to the knockout stages of the Champions League yet again.