Petr Cech has revealed Chelsea’s doctor had to ask more than three times for the stretcher bearers to attend the stricken Kurt Zouma at Derby County on Tuesday night, though the goalkeeper believes his helmet saved the French defender from more serious injury following their “huge hit” of heads.

The accident occurred near the close of the first half of Chelsea’s 3-1 Capital One Cup quarter-final victory at the iPro Stadium. Cech punched away a Derby corner and in doing so collided with Zouma.

With José Mourinho imploring the stretcher carriers to hurry up and Cesc Fàbregas and César Azpilicueta following their manager’s lead, Cech said the club’s doctor, Eva Carneiro, had to ask them repeatedly to enter the field.

“Eva was saying at least three times prior to that through the radio: ‘Bring the stretcher,’” Cech said. “We could hear it. I think that was why everyone was upset with the call. We heard: ‘Bring the stretchers;’ ‘Bring the stretchers;’ and: ‘Bring the stretchers.’ But nobody was coming. I think that’s why the players got involved. Overall I think the situation was handled well, everybody did the right thing. The main objective was to make sure the player was safe and he is safe.”

After the match Mourinho said he had been concerned and frustrated at the length of time before the stretcher arrived though the manager said he was informed of the bearers’ instruction that they are not allowed to run.

Cech suffered a horrific head injury in October 2006 at Reading during Mourinho’s first Chelsea tenure. Last year the Portuguese claimed the goalkeeper was “dying” following the clash with Reading’s Stephen Hunt that left Cech motionless having fractured his skull. Since then Cech has worn protective headgear and he believes this may have prevented Zouma from being more hurt.

“I think we clashed with heads. I had a huge hit on my right side and obviously when I got the ball away I was looking where the ball goes and it was a punch so I was happy with that,” said Cech. “But then I saw him lying on the floor. I was a bit concerned because we collided with a heavy clash.

“I think it was lucky he hit my helmet because the impact would have been much bigger. I think the helmet saved him, me as well. Because he hit most of the helmet and took away a little bit of the impact. He’s fine, the medical staff did really well to assess the situation. In this kind of clash you never know. He did not look so good to continue. Obviously it was the right choice. Now he is all clear hopefully. He is sitting there happy we won the game.”

César Azpilicueta and Cesc Fàbregas help carry Kurt Zouma off the field on a stretcher. Photograph: BPI/Rex

Mourinho believes the 20-year-old Zouma should be fine for Monday evening’s visit to Stoke City for Chelsea’s next Premier League match. Cech was asked if the incident brought back memories of his own head injury. “In football you have this situation quite often. You have the cross and everybody wants to win the header so there is always a possibility you will collide with someone.

“This is a common thing in football. So not every clash makes me think of that one,” he said before referring to the similar head injury Hugo Lloris suffered in November last year when he collided with one of Romelu Lukaku’s knees when Tottenham Hotspur played Everton. “If you see for example the Lloris one you say: ‘Oh, he was lucky,’ because it was a similar situation. But on that one [Zouma] no.

“The doctor was there quickly, everybody was there making sure he was OK. Our medical team and the referees they did really well. The other guys took a little bit of time but I don’t think the player was in danger at that time because the doctor was with him, Eva was with him.”

Chelsea are now in next month’s semi-finals. “We knew it was going to be a difficult night, they [Derby] have been flying this season,” said Cech, who wants the club to target all four trophies they remain in contention for. “You cannot say: ‘We leave this competition, we chase this competition,’ because in that competition you pick you have one unlucky game and you have nothing.”

n Monday Chelsea found out they will face Paris Saint-Germain, with their former player David Luiz, in the last 16 of the Champions League. Cech said: “It was my guess prior to the draw. So I was sitting there saying to the guys, we would have him or [Ricardo] Carvalho [of Monaco]. We got PSG. It will be interesting to see. Last season was a big match for us; we lost away then we had to chase the game at home and did really well. This time I expect the game to be as difficult as it was last year but let’s see what’s going to happen.”

Cech believes this Chelsea team can be compared to those from Mourinho’s successful first spell at the club only once a trophy has been won.

“I keep saying you can only judge teams at the end of the season when you see how much the team achieve,” he said. “Because in this moment we have been doing remarkably well but we have no trophy in our hands. So let’s see what’s going to be the case at the end of the season. Obviously this team has the potential and the quality to become one of the best teams in the Chelsea history if it proves by winning the trophies.”