Arsenal have claimed a memorable victory by beating Olympiacos 3-0 to progress to the Champions League knockout stages.

The Gunners are through to the Round of 16 for the 16th straight season after clinching the victory they required at the Karaiskakis Stadium to finish second in Group F after a dismal start to their European campaign.

Olivier Giroud was the hero for Arsene Wenger's side with a match-winning hat-trick to send the North Londoners home from Greece on an enormous high.

The French striker opened the scoring in the 29th minute when he squeezed a front post header from Aaron Ramsey's cross past Olympiacos keeper Roberto Jimenez, just five minutes after Mathieu Flamini's effort had deflected onto the crossbar.

Four minutes into the second half, Arsenal were two goals ahead when Giroud started the play which saw former Olympiacos loanee Joel Campbell heavily involved. The Costa Rican controlled well before dazzling the defence and supplying a lovely reverse pass for Giroud who finished coolly.

Less than 20 minutes later and the Gunners had skipped away to a three-goal lead when Olympiacos were penalised for handball when Nacho Monreal's goal-bound effort struck the arm of the outstretched Omar Elabdellaoui.

Giroud stepped up to the spot and confidently tucked his 12-yard attempt away to notch his very first hat-trick for Arsenal.

The magnitude of Arsenal's win cannot be ignored as Marco Silva's Olympiacos had won seven of their past eight Champions League matches at home prior to tonight.

The North Londoners join German giants Bayern Munich in the next phase after recording nine points in the group stage after losing two of their first three fixtures while Olympiacos drop to third and will now compete in the Europa League with Dinamo Zagreb finishing bottom.

2015/16 UEFA CHAMPIONS LEAGUE - GROUP F

Olympiacos (GRE): 0
Arsenal (ENG): 3 (Olivier Giroud 29'/49'/(PEN) 67')
Karaiskakis Stadium, Piraeus, Greece - 30,000