Manchester City rallied around Sergio Aguero after the club’s record goalscorer was admitted to hospital with a cardiological issue.

Aguero walked off in the 41st minute of Barcelona’s draw against Alaves on Saturday and underwent ‘a diagnostic and therapeutic process’.

It was the 33-year-old’s first start since leaving City in the summer and his former manager, Pep Guardiola, contacted the striker’s agent after the incident.

‘It’s difficult news for him and his family,’ Guardiola said. ‘We wish him well from all our people. Our chairman, we wish him a safe recovery. Health and life more important than anything else.

‘He is in good hands, he takes care of himself, we wish him a safe recovery and come back if he can – otherwise enjoy his life and what he has done. Be careful and be safe for the rest of his life.’

Kyle Walker, who was on the White Hart Lane pitch when Fabrice Muamba’s suffered a cardiac arrest during an FA Cup tie in 2012, added City’s players were in shock at the news.

‘I played with Christian (Eriksen) and it happened at the Euros to him and you think about him and the family,’ said the defender.

‘I hope Sergio is OK, I spoke to Christian a couple of weeks ago on text message. It is a surprise, we are fit athletes and we train every day. His health is more important that football at the moment.

‘I have seen it happen to a few people I have shared a dressing room with. Take your time, as long as it takes.’

Meanwhile, Guardiola claimed that Wednesday’s Champions League clash against Club Bruges is a bigger occasion than the weekend’s derby at Manchester United.

Victory over Bruges would leave City in a commanding position to seal qualification to the last 16 after reaching last season’s final.

‘This is more important than United – this game gives us incredible step forward to qualify,’ he said.

‘In the Premier League there are many games, here just six games and only three left. Games three and four are decisive– the most important games. We have to take it seriously to make a good performance and take a step forward in qualification.’