Groups E to H were in action in the UEFA Champions League on Tuesday night.
Alexis Sanchez scored a double after supplying Mesut Ozil's opener as Arsene Wenger's Gunners moved within three points of second-placed Olympiakos who they take on in Athens in the final group stage fixture on December 9.
In the other group encounter, German giants Bayern Munich easily accounted for Olympiakos with a 4-0 result at the Allianz Arena courtesy of goals from Douglas Costa, Robert Lewandowski, Thomas Muller and Kingsley Coman.
Chelsea went top of Group G thanks to a largely unconvincing yet comfortable 4-0 win over ten-man Maccabi Tel Aviv in Haifa.
Chelsea replaced FC Porto at the helm of the group after the Portuguese side were beaten 2-0 at home by Ukraine's Dynamo Kyiv, forcing qualification for the Round of 16 to the final set of group stage fixtures which will see Chelsea host Porto and Kyiv at home to bottom-placed Tel Aviv.
Barcelona produced a dazzling display at Camp Nou in hammering AS Roma 6-1 in Group E with Luis Suarez and Lionel Messi both scoring braces, assuring their place in the knockout phase for yet another season, as BATE Borisov held Bayer Leverkusen to a 1-1 draw in Belarus which keeps all other three teams in with a chance of finishing second.
And in Group H, Zenit Saint Petersburg progressed to the Round of 16 courtesy of a 2-0 home win over Valencia as Gent defeated Lyon 2-1 in France with a last-gasp Kalifa Coulibaly goal to move into second position ahead of their final fixture against the Russians.
2015/16 UEFA CHAMPIONS LEAGUE - GROUP STAGE SCORES