Antonio Conte blamed himself for Chelsea's 3-3 draw with Roma at Stamford Bridge on Wednesday night.
The Italian converted to a 3-5-2 system from his usual 3-4-3. Centre-back David Luiz started alongside Tiemoue Bakayoko and Cesc Fabregas in the centre of midfield.
And although the Blues went up 2-0 in the first half, courtesy of goals from Luiz and Eden Hazard, Conte felt that the system he implemented ultimately cost his side.
"The effort the players put in was the maximum and I thank them. We suffered in the first half and the decision to change system didn't pay off, as it took away all our guarantees. We were basically improvising and it showed, as we suffered under Roma's pressing.
"We scored two goals, but the sensation was always that we didn't feel in control of the match. I have to take responsibility, as it was my decision to change the system to make up for the lack of options. I changed the David Luiz position to strengthen the midfield and I don't think it worked, to be honest.
"It's not about injuries, but trying to get the best out of the team. The same players have been going all the time since pre-season. We've got three injuries, not seven or eight, but it's still an emergency situation for us.
"David Luiz had a problem with his calf, Bakayoko finished with a problem in his adductor and I hope it's nothing serious.
"Despite all that, we drew with a very good Roma side and I can only praise my players."