The Gunners centre-back says the team must go back to basics on the training ground after the second leg defeat to Barcelona on Wednesday night.
West Ham United travel to fierce rivals Chelsea this weekend looking to go level on points with third placed Arsenal in the Premier League.
The Whites' victory in November saw them seal their first back-to-back wins of the season in the Championship.
Everton are Arsenal are set to meet at Goodison Park on Saturday.
Tottenham Hotspur lost 5-1 on aggregate to Borussia Dortmund in the Europa League.
Liverpool secured a 1-1 draw with Manchester United in the Europa League on Thursday, which was enough to earn progress through to the last eight.
Ronald Koeman has done an excellent job at Southampton so far.
Martin Keown thinks Everton defender John Stones is lucky to be in the England squad.
The Croat shares his view on the race to reach Europe's elite competition.
Sunderland have come out on top in the last six meetings between the two Premier League strugglers.
The Arsenal midfielder joined the Cherries on loan over the summer in a bid to recapture his form and fitness.
Exciting Arsenal youngster divided opinion in clash with Southampton.
Everton-owned defender Luke Garbutt was spotted watching boyhood club Leeds United this week.
Arsenal should attempt to bring the 33-year-old back to North London.
Everton are reportedly closing in on Charlton Athletic striker Ademola Lookman.
Teenage striker Kazaiah Sterling was a class above in Tottenham Hotspur's FA Youth Cup win.
Gary Mackay Steven has not featured for Brendan Rodgers' Celtic side at all this season, due to injury.
Rangers lost 2-0 to Hearts.
Aston Villa are reportedly looking for a new defensive midfielder.
Leeds United's Charlie Taylor starred against Liverpool on Tuesday night.
Sepp Blatter was paid a £2.6m package last year, the first for which Fifa has disclosed the salary paid to its president and secretary general. Football’s world governing body published the figure in its accounts for 2015, which showed that a year of unprecedented corruption scandals had led to it losing $122m (£84m).
Glencore’s efforts to reduce fatalities among its staff have suffered a setback with the announcement that the death toll from an accident at a Congolese mine has risen to seven.
The Apple co-founder Steve Wozniak said he no longer recognises the company he built, thanks to creations such as the Apple Watch.