Jose Mourinho cursed the loss of Diego Costa after Chelsea restored their seven-point advantage at the top of the Premier League with victory over Stoke.
Goals from Eden Hazard and Loic Remy sealed a 2-1 victory at the Bridge, the strikes coming either side of a wonder-goal from well inside his own half from Potters midfielder Charlie Adam.
Costa started the game on the bench, but came on in the second half, only to limp off shortly afterwards with a recurrence of a hamstring problem.
The Portuguese boss admitted it was a risk to introduce the Spaniard, but said he felt it was required.
"If my medical department decides to take four weeks to recover Diego this would not happen but in football we need risks," Mourinho told Sky Sports. "I risk sometimes, as a manager in a result I don't like.
In pictures: Chelsea 2-1 Stoke
"We played more offensive and if the opponent scores I don't kill myself for that.
"But in all the scans they did two days ago the muscle was clear, the image was clear and the player trained twice 100 per cent, when he did much more than he did today.
"We put him in dozens of actions and the result was correct. My medical department is fantastic so there is no problem. Next week plays Remy and Drogba, we wait for Costa again. For sure with that injury it will be a couple of weeks minimum."
The Blues sit seven points clear with a game in hand at the top of the Premier League, but Mourinho still isn't counting his chickens.
He added: "We needed six wins and a draw, now we need five wins and a draw. It was a difficult game but we deserved the victory."