A Stoke steward made ridiculous claims that Costa deliberately pushed him as he retrieved a loose ball to take a corner, reporting the incident to referee Anthony Taylor despite his fellow stewards apparently attempting to talk him out of the complaint.
Chelsea themselves rubbished the allegations and, even if the incident appears in Taylor’s report, a cursory glance at television footage will show the FA there is no case for Costa to answer.
The same cannot be said when it comes to Chelsea’s worst league run — three consecutive defeats — in 16 years.
At this stage of last season, Chelsea had scored 30 goals, of which 11 had come from Costa himself. Fast forward to this most trying of campaigns and those figures stand at 16 and three, Costa having scored six times in his last 28 games in all competitions.
With Mourinho forced to watch from a hotel as he served a one-game stadium ban, there were few visiting players or coaches willing to comment on the defeat.
Midfielder Ramires said: “We played very well but we didn’t score and football is that. If you play very well and concede a goal and don’t score a goal, you’ll lose the game.”
That may not be the most incisive analysis of Chelsea’s current problems but it is as accurate as any. Willian and Eden Hazard looked back to their former creative selves, Pedro deserved a goal with a swift and skillful move that ended with a shot hitting the post, and late substitute Loic Remy should have had a penalty after being forced to leapfrog goalkeeper Jack Butland.
But without the imperious Costa of last season — all swagger, constant energy and motion, and a dead eye for goal — there is no end product.
“We definitely did enough to get a result here but when things aren’t going your way you don’t get the luck you deserve,” said Chelsea’s former Stoke goalkeeper Asmir Begovic. “We hit the post, we slipped over when we had open goals, we are making things hard for ourselves.
“You can see from the game today it is not something you can pinpoint. We are getting punished for little bits and pieces but eventually it will turn.”
That is far from a given, what with the depth of the malaise now afflicting Chelsea and the cloud of controversy and dissatisfaction that seems to follow Mourinho, as closely as Stoke defender Ryan Shawcross man-marked Costa at the Britannia.
Mourinho, serving a ban for his verbal assault of the match officials after last month’s defeat at West Ham, delivered his standard pre-game team talk at the Chelsea hotel before sending off his charges to the stadium while he settled down to watch on television.
It was a unique set of circumstances, as Stoke manager Mark Hughes conceded, but the net result was similar and familiar to what has happened all too often already this season.
“I think it’s not a blip — it’s far from a blip now,” said the Stamford Bridge legend Frank Lampard, fulfilling television duties. “Chelsea shouldn’t be where they are. They’re losing games regularly. They need to turn the corner quickly.
“Watching them there I saw glimpses of what they’re going to need to turn the corner. Brighter play, sharper, working harder. I couldn’t really fault the performance. They just didn’t get the bit of luck they needed to win the game. They need to now get results — simple as that.”
An improvement in defending is also required — the space allowed to Marko Arnautovic to volley in the game’s only goal early in the second half underlines the size of the task facing Mourinho.
He will return from a two-week break to face a home fixture against a Norwich side that moved above Chelsea in the table on Saturday.
“Not only Jose but Chelsea’s bench is probably one of the more animated ones,” said Hughes. “I wasn’t aware of them today, I don’t know if they were jumping up and down or whatever.
“That surprised me somewhat because they usually are quite animated but you can feed off that energy and use it to your own end. Certainly our crowd have done that in the past with other managers. They didn’t get the opportunity today but thankfully the fans didn’t need Jose there in the dug-out.”
Butland 8; Johnson 6, Shawcross 8, Wollscheid 7, Pieters 7; Whelan 6, Adam 6 (Affelay 79, 7); Shaqiri 9 (Diouf 82), Bojan 7 (Cameron 71, 7), Arnautovic 8; Walters 6.
Ireland, Wilson, Crouch, Haugaard.
Begovic 7; Azpilicueta 5, Zouma 6, Terry 6, Baba 5 (Oscar 70, 6); Ramires 5 (Remy 77, 6), Matic 5; Pedro 7 (Fabregas 70, 6), Hazard 7, Willian 8; Diego Costa 5.
Mikel, Kenedy, Cahill, Amelia.
A Taylor 5