Manchester City manager Pep Guardiola has dismissed reports his assistant coach Mikel Arteta was involved in an altercation with Lionel Messi after the 3-1 Champions League win over Barcelona.

Speculation emerged in the immediate aftermath of Tuesday's game at the Etihad Stadium that Messi, who opened the scoring for the LaLiga champions, shouted angrily towards a player departing into the City dressing room.

City striker and fellow Argentina international Sergio Aguero stated he saw nothing untoward, while midfielder Fernandinho described claims he was at odds with Messi as "absurd".

Former Everton and Arsenal midfielder Arteta was surprisingly the next name in the spotlight, with Spanish TV channel La Sexta claiming he said to Messi: "Who are you waiting for? Go on to the changing room, you twit."

Spanish radio station Onda Cero subsequently reported a denial from Arteta but, speaking at a news conference ahead of Saturday's Premier League match against Middlesbrough, Guardiola dismissed the matter out of hand.

"I spoke with Arteta," he said. "It's impossible, he admires so many things about Barcelona, the institution, about Messi in this case.

"And knowing Mikel as I know him, he's one of the best people I've met in my life, it's impossible that he could have an argument with another excellent person like Messi. Impossible.

"First it was Fernandinho, now it’s Arteta, let’s see who it is tomorrow. Let’s see if you finally guess."

Guardiola reported encouraging news on the injury front, with right-back Bacary Sagna returning to training following a hamstring injury.

The game comes too soon for Fabian Delph, but the England midfielder is training on his own to build fitness after undergoing surgery on a hip problem, while Guardiola can decide whether to call upon captain Vincent Kompany.

"Fabian, after the operation in Barcelona with Ramon Cugat, is going really, really well," he said. "When I spoke with him and the doctor they say there is no pain now. He is happy. But he is still out and training alone.

"And Bacary is getting better. I think after the international break he will be fit.

"Fortunately, we have a marvellous medical and physio department. We have 21, 22 players available, so that is fantastic in a period when there are [normally] a lot of injuries."

On the prospect of Kompany completing 90 minutes for the first time since his latest injury setback, he said: "Yeah, maybe.

"I have to think this afternoon about my team and speak to the physios about their physical conditions."