Arsenal fear Sanchez injury loss could be 'big blow'.
Manchester City squandered a gilt-edged opportunity to close the gap on Premier League leaders Chelsea when they let slip a two-goal lead to draw 2-2 at home to struggling Burnley on Sunday.
Arsenal missed the chance to heighten the congestion at the top of the Premier League and suffered fresh injury blows when a frustrating 1-1 draw at Norwich City failed to take them alongside leaders Manchester City and Leicester City on Sunday.
Chelsea's unbeaten start to the season ended with a dramatic 2-1 defeat at Newcastle United; Champions Manchester City took full advantage of Chelsea's surprise reverse to cut the gap at the top.
Photos from the Euro 2016 qualifying matches played across Europe on Saturday
Images from the Champions League round of 16 second leg matches played on Tuesday
Premier League leaders Arsenal showed their class as they comfortably beat north London rivals Tottenham Hotspur 2-0 to book a place in the FA Cup fourth round in an electric atmosphere at the Emirates Stadium on Saturday.
Chelsea returned to their early-season form to open up a five-point lead in the Premier League, Cristiano Ronaldo and Lionel Messi continued to make mincemeat of La Liga defences and Juventus extended their lead in Serie A. In France, Olympique Lyonnais retained top spot with a 2-0 win at RC Lens.
Arsenal maintained their challenge for a first trophy in nine seasons when they beat Liverpool 2-0 at the Emirates Stadium to open up a five-point lead at the top of the Premier League on Saturday.
Jose Mourinho got the better of old adversary Arsene Wenger once again as Chelsea showed their strength-in-depth by reaching the League Cup quarter-finals with a 2-0 win over London rivals Arsenal on Tuesday.
Liverpool produce an irresistible performance to dismantle a toothless Tottenham Hotspur 3-0 and Arsenal were held 1-1 by Leicester City in the Premier League on Sunday.
An Aaron Ramsey strike and a Kalidou Koulibaly own goal gave Arsenal a 2-0 victory over Napoli in the first leg of their Europa League quarter-final, while Chelsea beat a stubborn Slavia Prague 1-0.
This and more from the happenings in the world of football
Danny Rose scored a second-half equaliser to cancel out James Milner's penalty as Tottenham Hotspur came from behind to draw 1-1 with Liverpool at White Hart Lane on Saturday.
Images from the UEFA Champions League matches played across Europe on Wednesday
Coach Pep Guardiola was left thrilled after ManchesterCity revived their Champions League bid by beating his old club Barcelona 3-1 in a gloriously open Group C encounter at the Etihad Stadium on Tuesday.
Cristiano Ronaldo renewed his personal battle with Lionel Messi by scoring his 71st Champions League goal, putting him three behind the Argentine's newly-set record, in Real Madrid's 1-0 win at FC Basel on Wednesday.