Arsenal boosted their hopes of advancing from the Champions League group stages with a comfortable 3-0 win over Dinamo Zagreb at the Emirates.It puts Arsene Wenger’s men on six points in Group F, three behind second-placed Olympiakos going into the final round of matches next month.The clash was a must-win game for the Gunners if they were to stay in the competition.A Mesut Ozil header was followed by Alexis Sanchez’s double against a relatively poor Zagreb outfit, but there were positive performances to note, with the goalscorers and Joel Campbell putting in an impressive shift.Sanchez was provider for Ozil to head home from close range, before Leonardo Sigali’s defensive mistake lead to Nacho Monreal’s instinctive reaction to provide for the Chilean forward. He then added a third to all but confirm the win after good play by Campbell on the wing. Going into the final game at Olympiakos, Arsenal will need to be on form as head-to-head takes precedent over goal difference. Arsenal were beaten by the Greek side last time out in September and the next round of games takes place in two weeks’ time.Zagreb were without midfielder Arijan Ademi, who failed a drugs test after the previous match against Arsene Wenger’s men, where the Croatians won 2-1. He was subsequently banned for four years, with Wenger saying this week that UEFA ‘basically accept doping’.Arsenal started the evening not only hoping for a victory in north London, but in the hope that Olympiakos would lose heavily against Bayern Munich.In front of a far from full Emirates Stadium, the hosts had a lacklustre start, creating few chances and posing little threat.Santi Cazorla blazed a chance high and wide before Campbell was at the heart of a lively interchange after 11 minutes.The Costa Rican attacker led a passing move which saw the play move from the right to Sanchez on the left-hand side. The Chilean controlled, but his hesitation saw Zagreb men close in on him and the 26-year-old could not get a shot off.Arsenal grew further into the contest and Olivier Giroud missed the ball when he went for an ambitious overhead kick, moments before the hosts took the lead.You could almost feel the relief around the ground as Ozil converted. After Dinamo surged forward, the Gunners hit them on the couter and made them pay. The ball was quickly moved between the team before Sanchez’s pinpoint cross to the German playmaker, whose deft, controlled header beat Portuguese goalkeeper Eduardo after 29 minutes.Arsenal doubled their lead four minutes later when they capitalised on sloppy defending. Sigali’s clearance was poor, when Monreal intercepted on the edge of the box, surging into the area and crossing for Sanchez to coolly convert for his first Arsenal goal in over a month.The home side were comfortable in restricting the visitors. Campbell could have made it three when a good passing move involving Ozil, Sanchez and the 23-year-old, but Goncalo Santos’ clearance went up in the air. Campbell volleyed from 14 yards, but he made a poor connection and fired wide.Campbell did impress in the run up to Arsenal’s third goal after 69 minutes. He cut in from the right and his reverse pass cut open the Zagreb defence, Sanchez latching onto the ball before showing composure to beat Eduardo and fire into an empty net.More brilliant link-up player before Ozil and Sanchez saw a sumptuous ball dinked over the top by the latter, with the former heading past Eduardo and just past the post as Arsenal could afford to showboat with minutes remaining.There was also some additional positive news for Wenger, as Aaron Ramsey made his comeback from a hamstring injury, after over a month out.Elsewhere in Group F, Pep Guardiola’s Bayern Munich defeated Olympiakos 4-0 at the Allianz Arena. 1 The clash was a must-win game for the Gunners if they were to stay in the competition.