STAMFORD BRIDGE, LONDON — It took Diego Costa just 57 seconds to open his Stamford Bridge account on Tuesday.
Since returning to west London, strikers firing blanks has been a major headache for Mourinho, but now Costa has shown his manager need worry no more.
"I expect Diego [next season], and Diego is a team player who works a lot for the team and is not just about goals," the Chelsea manager replied when asked in the post-match press conference what we can expect from his newest striker.
"[He is] the player we have been waiting for since last season. This is the player why we didn't buy a striker in the last winter market.
"We have him, and hopefully everything goes well."
On Tuesday night's evidence, it will.
Costa's display was that of a man who knows he belongs at Chelsea.
A capacity crowd had turned out for a pre-season friendly to see if he really was the real deal, and it departed into the west London night knowing it had just seen a future legend of the football club.
He owned Stamford Bridge. Costa delivered.
His first goal demonstrated the instincts we saw Costa produce in an Atletico Madrid shirt last season, reacting quickest to lose his marker and latch onto Ramires' through ball to open the scoring with less than a minute played.
Costa's second may have been fortunate—Andre Schurrle's effort bouncing off the post into his path to tap into an empty net—but his positioning was expert. He was in the right place at the right time in the way all great strikers are.
"You can say that [Costa's transfer fee was a bargain] because the market is crazy, as everybody knows," Mourinho continued. "The values in the market are very, very high."
Costa is a player who has already delivered titles in his career and was a major reason why Atletico reached the Champions League final last season.
He impacts games considerably, bullying defenders into submission.
Lukaku may go on to be quite the player, but right now, he is very much in Costa's shadow. The Belgian would have been for the foreseeable future had he remained at Stamford Bridge, too.
It may be a simple way of looking at things, but when considering his £32 million fee, Lukaku's sale means Chelsea paid just £4 million net for Costa.
Sociedad faced him in La Liga last year, so their defence would have been au fait with Costa's threats at Stamford Bridge.
Perhaps that meant they carried an element of fear into the game or were simply caught cold in pre-season. Whatever it was, they couldn't control him for the hour he spent on the field.
And that's going to be the problem the other 19 Premier League sides are going to face, beginning with Burnley next week.
How do you control Diego Costa?
It doesn't seem you can.
Garry Hayes is Bleacher Report's lead Chelsea correspondent. Follow him on Twitter @garryhayes.