Arsène Wenger has refused to apologise for pushing José Mourinho as the rival managers were involved in an ugly first-half spat, while Chelsea were left facing awkward questions themselves in the wake of this victory over their medical staff’s initial assessment of the severity of a head injury sustained by Thibaut Courtois.

Wenger had been infuriated by Gary Cahill’s poor challenge on Alexis Sánchez on the touchline, a tackle which earned the England centre-half a caution, and marched out of his own technical area and across that of his opposite number. Mourinho stood in the Frenchman’s way, ushering him back, with the Arsenal manager pushing him back. The pair clashed again seconds later with the fourth official, Jonathan Moss, duly stepping in to separate them and the referee, Martin Atkinson, subsequently speaking to both.

There will be no retrospective sanction given the clash was witnessed at the time but, while the incident merely served to inflame an already tense occasion, Wenger expressed no regret. “What is there to regret?” he asked. “I wanted to go from A to B, and somebody confronted me before B without any sign of welcome. B was Sánchez, to see how badly he was injured.” The Arsenal manager suggested Cahill’s foul was worthy of a red card and, asked what Mourinho had said to him, added: “Honestly, I don’t listen to what he says. Push him? You would know if I really tried to push [him]. Come on.”

The pair, who share a strained relationship born of regular clashes since Mourinho arrived in English football in 2004, did not acknowledge each other on the final whistle, once Chelsea had reasserted their five-point lead at the top of the table and condemned Arsenal to a first league loss of the season. “It becomes heated because it’s a big game, big clubs, big rivals, an important match for both teams,” said Mourinho, who has not lost in 12 meetings with Wenger. “These conditions make a game of emotions. After that,there are two technical areas. One for me, one for him. He was coming into my technical area and not for the right reasons, to give some technical instructions. He was coming to push the referee for a red card, and I didn’t like that.

“But no problem. I think Jonathan Moss did a good job, and Atkinson too. I’ve done so many wrong things in football, sometimes due to emotion, but not this time. This time I was just in my technical area and it was not my problem. Game over. Story over.”

Mourinho was less comfortable discussing the issue surrounding Courtois, who was floored after sustaining a 10th- minute head injury when connecting with Alexis Sánchez’s right thigh. Two of the home side’s medical staff sprinted on to the pitch to assess the Belgian and, having examined him for 56 seconds and spoken to the player, were satisfied the goalkeeper could play on. Yet 13 minutes later he had sunk to his knee with liquid coming out of his right ear, was substituted, assessed by a Premier League appointed doctor in the dressing room and taken to hospital for precautionary tests. It was later confirmed he had suffered mild concussion and was kept overnight in hospital for observation.

Chelsea’s staff technically followed the new guidelines set out by the Premier League for this season – Fifa have since stipulated a three-minute timeout should be taken in such cases to make a more thorough assessment of a player’s state of fitness – with the incident merely serving to underline how limited the recently adopted measures are. “He had hospital tests as a precaution,” said Mourinho. “But we think nothing to worry about.

“On the bench I don’t communicate with the doctors. I just get [their] decisions. Can he stay? Yes. He has to leave? OK. No time to discuss, no medical qualities to discuss. They said yes at first, then after that said no. I was just worried for the kid. We have Dr Biosca, the head of the medical department, and he has his people. I always tell them that, when I’m on the bench, I don’t want to communicate with them. I just want them to give me a decision. They gave me their decision. For me, that’s correct. The club doctor or medical department should take control and responsibility.”

Yet there was criticism of the system, whereby a member of a club’s staff effectively make the assessment as to whether their player should continue, from Taylor Twellman, the former New England Revolution player who was forced to retire after suffering a serious head injury.

“So you guys want me to be convinced that the EPL Concussion Protocol has made a difference?!” he tweeted. “Courtois wasn’t evaluated properly.”