Victor Moses' stoppage-time winner rescued Chelsea's Champions League campaign last night. The substitute's 94th-minute header gave Chelsea a 3-2 win over Shakhtar Donetsk to leave them on the verge of qualification.
The manager, Di Matteo admitted it was a "crucial" victory but his difficulties were not limited to the pitch as he revealed it was "not easy" to tell captain John Terry he was not fit enough to play.
Chelsea are second in Group E, joint Shakhtar on seven points and one point ahead of third-placed Juventus. Had Chelsea drawn last night, as they looked set to do before Moses' goal with the last action of the match, then they would have needed to avoid defeat in Turin on 20 November to stay in the competition.
"It was crucial for us to win the game," Di Matteo said. "We knew we needed to score a goal from that set-play at the end, and we did. We knew it was a must-win game. We didn't want to expose ourselves too much, but we did have to towards the end to win it."
Chelsea are likely to need four points from their final two games, the second of which is Nordsjaelland at home, to reach the round of 16. As long as they draw in Turin, qualification will be in their hands.
"It's not going to make things easier, but it's going to give us a good chance to qualify," Di Matteo said. "It'll probably go down to the last game, and the last kick of that as well."
Chelsea played without Terry, available but left on the bench, and Di Matteo said: "I'm very happy that he's back available for us after the ban.
"But considering the last four weeks in his professional life, he's had one competitive game, and I thought we needed players who were 100 per cent match fit for a game like this. I'm not going to comment on the private conversation with my players, but it's not easy to tell a player that he's not starting the game."
Di Matteo admitted there was an element of fortune. Shakhtar were the better team for most of the evening, conceding three goals from their own defensive errors. "In terms of the timing of the winning goal, you probably could agree that there was an element of luck," Di Matteo said. "It was basically the last kick of the game."