When Antonio Conte embraced Diego Costa at the final whistle on Saturday, sharing a joke and a laugh together, he might have wondered how differently this season could have gone. When Conte arrived in July, Costa wanted to go back to Atletico Madrid and he admitted on Saturday that he was “about to leave” before the move fell through.

Six months on, Costa has 14 Premier League goals and is likely to finish the season with the Golden Boot, as well as his second Premier League title. He is certainly going to out-do the 20 he scored on his way to the 2014-15 title. With all due respect to Harry Kane and Sergio Aguero, Costa is the best striker in the country right now.

The fact that Chelsea did not sell Costa and buy back Romelu Lukaku, as they had initially hoped to, now looks either far-sighted or fortunate. Costa revealed on Saturday just how close he had come to ending his time here, because of the family pull of returning back to Madrid.

“I had the possibility to go to Atletico,” Costa said, “because of a few things, family, the life I have there. I wanted to change for family reasons. Not because of Chelsea, because there is a lot of love with the supporters here, so I’m very happy. I was about to leave. But it wasn’t to be. I continue to be happy here, I’m very content.”

Costa said that the trust he feels from Conte has been a big part of his revival as a player. “It was important, too, that the manager, from the very minute, said he counted on me,” Costa said. It is true that Conte has worked very hard on Costa, getting him fitter and more focused, but the biggest improvement has come from within Costa himself.

After picking up four yellow cards at the start of the season, the fact that Costa survived so long before receiving a fifth speaks volumes to his improved disciplinary record, and his ability to resist provocation. Costa has always felt more sinned against than sinning but he does at least now know how to channel his passion in the right way, and how to avoid getting booked.

“I thought about it, and knew I had to improve that aspect, because, here in the Premier League, the reality is there’s no mercy,” Costa said. “A lot of the time it seemed like they were against me. There was no other way, because if they’re not going to change, I had to change.”

The result is a player who looks happier, sharper and better now than he has done at any point in his two and a half years at Chelsea. His improvement mirrors the improvement of the whole team, and it is remarkable just how quickly things have changed after just half of a season under Conte.

Costa spoke of the intense personal loyalty that the players already feel towards Conte, a bond that is clear every time he runs onto the pitch to do his post-match victory hugs. Neither Conte nor Costa revealed what their shared joke was after Saturday’s game, but the connection between the two men was obvious.

“The truth is that the manager is good with the players, always making jokes with us,” Costa said. “That is good for us, to have a manager who is not just a boss but like a person we can talk with, someone whose support we can count on in difficult moments. He is calm with the players and you can see the people love him more all the time.”

Diego Costa has a strong relationship with Antonio Conte (Getty)

Conte loves Costa too, and understandably so, given that his goals are going to win Chelsea the title. Costa was better than ever on Saturday, scoring a brilliant goal five minutes from the end to cap a majestic performance. In the first half he nearly scored a goal reminiscent of Dennis Bergkamp, taking the ball out of the air and shifting backwards into a shooting position only to be blocked by Lee Grant.

Everyone knows that Costa is a good player, but Conte spoke afterwards of how his bubbly personality helps to lift the whole team. “Diego is a good guy and for him it is important to joke,” Conte said. “But when it is the moment to work, he works. He is a Brazilian. He is always happy and he wants to show this. For us it is very important because when you have this type of player keeping the atmosphere always electric, with good positivity.”