Middlesbrough dropped beneath Burnley in the Premier League table as a result of their loss at Turf Moore, with Boro boss Aitor Karanka fuming about the manner of the goal they conceded.
Yet it was not former Barcelona and Manchester United goalkeeper Victor Valdes who was the target for his anger, despite the stopper allowing Gray’s attempt to squirm beyond him, but his whole team as they were undone by a route-one attack Karanka had warned them to take heed of.
It was the things that we had been working on all week.
“We’ve lost from one ball that we knew they played this style,” the Spaniard said.
“We’ve done a lot of good things and to concede like that, it’s frustrating.
“It was the things that we had been working on all week, the things that I had been showing them in the videos happens, so it’s frustrating.”
Gray’s volley came 10 minutes from time to earn Burnley a 1-0 win.
The former non-league forward had not scored since netting against Liverpool in August, after which historical homophobic posts on social media came to light that saw the Football Association hand him a four-game ban.
He has not been a regular since returning, but he provided the key contribution in a dull affair with a late strike that earned the Clarets a sixth home win of the season.
It was unsurprising to see a tight game unfold, although Cristhian Stuani had a chance to break the tension with a 12th-minute half volley that he fired wide having been put through over the top by Antonio Barragan.
George Boyd’s smart Cruyff turn caught out Fabio and from his cross a scramble ensued, with Ashley Barnes unable to connect with a wild scissor kick and the ball then bouncing past Calum Chambers, who may have moved his arm toward it as it brushed his elbow. Referee Craig Pawson was not interested.
Boyd drilled a short free-kick at Valdes, but the half closed at a suitable stalemate, with the five yellow cards Pawson dished out far outweighing the number of opportunities.
A sixth caution arrived just after the break, and there could be no quibbling about it as Jon Flanagan scythed down Gaston Ramirez on the byline.
Stuani provided Tom Heaton with more of a test from a header from a Ramirez corner before a meaty Stephen Ward challenge on Barragan saw temperatures rise once more and Pawson turn to his yellow card again.
Pawson’s notebook, which would include 11 bookings by the end, was filling in with substitutions too as Sean Dyche made three within 11 minutes. The changes soon paid off.
From Heaton’s long free-kick, substitute Sam Vokes’ flick-on was met by a viciously-struck volley from Gray and, although it was straight at Valdes, the power meant the Spaniard could only watch as it squirmed away from him and over the line.
Burnley: Heaton, Flanagan, Keane, Mee, Ward, Boyd, Marney (Defour 75), Hendrick, Arfield (Gudmundsson 77), Gray, Barnes (Vokes 66). Subs Not Used: Kightly, Robinson, Tarkowski, Darikwa. Booked: Boyd, Mee, Flanagan, Ward, Gray, Hendrick. Goals: Gray 80.
Middlesbrough: Valdes, Barragan, Chambers, Gibson, Da Silva, Forshaw, Clayton, de Roon (Friend 87), Stuani (Traore 86), Negredo, Ramirez. Subs Not Used: Bernardo, Leadbitter, Rhodes, Guzan, Downing. Booked: de Roon, Ramirez, Barragan, Da Silva, Negredo.
Att: 21,562 Ref: Craig Pawson