Andre Gray volleyed in his second Premier League goal 10 minutes from time to earn Burnley a 1-0 win over Middlesbrough at Turf Moor.
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.
Last year's Championship player of the year has not been a regular since returning, but he provided the key contribution in a dull affair here with a late strike that earned the Clarets a sixth home win of the season.
"We've lost from one ball that we knew they played this style," Middlesbrough boss Aitor Karanka 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.
"Victor is an amazing keeper and played for Barcelona - you need to go to the last month and a half, two months, when he's saved us a lot of times. I can't understand why we have to criticise Victor Valdes."
It had been four years since Burnley had scored in a Boxing Day encounter and their 3-0 loss to Hull 12 months ago was their final defeat before a 23-match unbeaten streak guided them to the Championship title.
They pipped Boro to that crown, but ahead of kick-off here it was Aitor Karanka's men who were one point better off in their respective battles against the drop.
However, at a venue where 16 of their 17 points had been accrued, the Clarets would have circled this affair, and the New Year's Eve clash with Sunderland, as pivotal ones.
It was unsurprising to see a tight game unfold given how evenly matched the two outfits are, 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.
There was little of note to report at the other end either, aside from Ashley Barnes' try being pushed around a post by Victor Valdes, although the half's biggest incident did occur at that end.
George Boyd's smart Cruyff turn caught out Fabio and from his cross a scramble ensued, with 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, a man in the spotlight for the past couple of weeks having not sent off Marcos Rojo before dismissing Jamie Vardy, 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.
However, Boro were unable to make either that free-kick count, nor a subsequent direct one that Ramirez floated harmlessly at Tom Heaton.
Stuani provided 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.
It was Gray whose 23 goals kept the Clarets ahead of Boro in the race for the title last year, and his second of the season we enough to lift them back above Karanka's side at the next level here.