Manchester City manager Roberto Mancini was involved in a training ground bust-up with volatile forward Mario Balotelli on Thursday, the Manchester Evening News reported.
Celtic manager Brendan Rodgers has a goalkeeping dilemma to resolve before ManchesterCity turn up for their Group C Champions League match in Glasgow on Wednesday.
Bradford City produced another giant-killing to reach the quarter-finals of the FA Cup.
Premier League newcomers Watford suffered a League Cup upset in a 1-0 loss at Preston North End while five-times champions Aston Villa overcame plucky Notts County 5-3 after extra-time to reach the third round on Tuesday.
Thirteen teams have now qualified for the last 32 including Bayer Leverkusen, FC Zurich and Lazio who had already secured places in the next stage of the competition.
Defender Filipe Luis has rejoined Atletico Madrid from Chelsea in a reported 16 million euro ($17.66 million) deal, the Spanish club said.
Former European champions Celtic were helped by two own goals as they thumped Astana 5-0 at home and a late goal from Wissam Ben Yedder gave Sevilla a 2-1 win at Istanbul Basaksehir in torrential rain.
Manchester City maintained their perfect start to the season with a 2-0 victory over promoted Watford as champions Chelsea suffered a shock 2-1 home defeat by Crystal Palace on Saturday.
First win for Liverpool manager Klopp, City thrash Palace 5-1
A summary of Wednesday's matches in the UEFA Champions League.
Images from the UEFA Champions League matches played across Europe on Wednesday
Lionel Messi, Luis Suarez and Neymar combined to devastating effect as Barcelona swatted Celtic aside 7-0 at the Nou Camp to lay down a marker in Champions League Group C on Tuesday.
Barcelona battled back from a goal down and scored twice in the second half to overcome hosts Borussia Moenchengladbach 2-1 in their Champions League Group C match on Wednesday despite the absence of the injured Lionel Messi.