London - Jose Mourinho hopes Diego Costa's winning goal against Norwich City will prove to be a turning point for the Chelsea striker.
The Spain forward has come in for growing criticism after struggling to recapture the form he showed during his club's march to the Premier League title last season.
Costa again missed a number of chances against Norwich before securing Chelsea's first win in four league games with the 64th-minute winner in a 1-0 success at Stamford Bridge on Saturday -- only his third goal in 11 Premier League appearances this season.
Chelsea manager Mourinho admitted his player has been feeling the strain, but believes Costa can now begin to put a difficult period behind him.
"When you don't score goals, you get heavier," said Mourinho. "Every game that you don't score goals, you get 5kg more. You get heavy and the pressure is there.
"In the first half he (Costa) misses two chances. The second one, in the last minute, is really a big one. So it was important for him. Important for us, the result and the goal, but I think also for him."
The Portuguese boss added: "He's working well, he's a happy guy, he tries everything. He's positive, so if I had to choose somebody to score the winning goal, I would go exactly with him.
"Everything is connected. I think when you are full of confidence it's not just about goals, it's also about -- I don't know if it's the right word -- but fluent.
"You are fluent in your decisions, you choose well your movements, you choose well the number of touches, when to hold, when to keep possession, when to touch, first touch.
"When you lose confidence, you lose this fluent game. Yes, he can do much better, but again, yes, one goal is very important."
And the manager believes Costa is benefitting from showing more discipline on the field.
"He's doing well. He had three yellow cards in 16, 17 official matches in the season.
"He's not responding, basically, to provocations. Little things are the salt and the pepper of football. He's behaving well and everything is fine."
Chelsea remain in the bottom half of the table with a third of the season gone yet while Mourinho has written off his side's title hopes, he still believes they can finish in the top four.
"We have to go game after game. But I said already in the press conference yesterday that the fourth position for me is not an impossible mission," he explained.
"If you ask me the title, I would say impossible mission. Maybe Tom Cruise can do it," Mourinho joked.
"It's complicated because you have to recover points from four candidates.
"But to recover positions and points to teams that normally are in the middle of the table and to grab one of the ones that go up and will also have a little bit of a collapse for sure, because everybody will have.
"The fourth position is a difficult position but a possible target. But match after match. Now is Maccabi (Tel Aviv in the Champions League) and we hope we can win and maybe the Porto-Dynamo result allows us to qualify before the last match, which would be good.
"But if we have to win the last match at home, let's go for that."
Norwich manager Alex Neil was frustrated his side were denied a first-half penalty when Willian challenged Robbie Brady, claiming it was the latest in a succession of decisions to go against his team.
"I generally don't say anything about referees because they have a hard enough job but it is getting extremely frustrating," he said.
"When you are one of the smaller clubs it becomes extremely difficult to accept because those minor decisions mean a great deal to us as we might not have five or six opportunities to score.
"So when you do feel you deserve a penalty you would like it to be awarded. That is where the frustration lies."