Forty-three-year-old substitute goalkeeper Craig Gordon produced an incredible stoppage-time save to earn 10-man league leaders Hearts a potentially vital Scottish Premiership victory at Dundee.
After Claudio Braga fired the visitors in front, goalkeeper Alexander Schwolow was shown a straight red card following a VAR review just before the break.
Dundee dominated possession in the second half, but were unable to find a way past veteran Gordon, making his first appearance since Scotland beat Denmark to qualify for the World Cup.
Derek McInnes’ Hearts move six points ahead of both Celtic and Rangers, with Danny Rohl’s team in action later on Sunday against Aberdeen.
Dundee stay ninth, having failed to find a fourth successive top-flight victory for the first time since 1999.
The home side started brightly off the back of three consecutive wins and Schwolow was forced into action, palming away a Billy Koumetio header.
However, Hearts slowly took control and went in front with their first shot on goal as Braga fired home via the post from the edge of the box.
The goal came from two simple forward passes, but Dundee were furious it was allowed to stand, after Cammy Devlin took a free-kick some distance from where the foul took place.
Still, Steven Pressley’s team were given a route back into the contest when Schwolow wiped out Tony Yogane on the edge of the box.
The officials originally gave Hearts a free-kick for offside, but replays showed Yogane was onside and referee Ryan Lee sent the goalkeeper off.
Despite their numerical advantage, Dundee were unable to breach a stubborn Hearts defence after the break, as Gordon saved from Koumetio and Drey Wright.
However, he appeared beaten in the 94th-minute when Emile Acquah headed towards his bottom left-hand corner, but Gordon sprung athletically to his left to claw the ball it to safety with one of the great saves.
Title-winning campaigns are built on certain wins, certain performances and certain moments.
Gordon’s save was as good as a goal at the other end for Hearts and might prove decisive come May.
Imagine Gordon Banks against Brazil in 1970 in reverse – with his weight going the other way, the ball was all but over the line until Gordon stuck out a big left hand.
There was no surprise McInnes and his Hearts players went to one man on the full-time whistle.
“We shall not be moved” belted out from the away end. They believe.
For Dundee, they will regret not taking at least a point.
They had more possession, more shots, more shots on target and far more touches in the opposition box, but were unable to make their pressure count.
Acquah was halfway to the corner flag celebrating before he realised what Gordon had done.
Still, this performance and their recent results would suggest they are unlikely to be dragged into a relegation fight this season – an impressive turnaround given their early-season struggles.
Dundee manager Steven Pressley: “I even thought 11 v 11, we were the better side. We carved out the better opportunities and we were aggressive in our pressure. It was very much what I wanted to see.
“It was just the fine margins. There were a lot of really good things among the performance, and of course, a real world-class save at the end.
“We’re trying [for reinforcements]. We’re hopeful we can get something over the line.”
Hearts manager Derek McInnes: “Any teams that have a successful campaign, they’re the bedrock – digging out results like that 1-0. The question was asked of us, there’s no doubt about it.
“The fans helped us win today. It felt significant and I really hope it is. That feels like the best three points of the season and we’ve had some big afternoons.
“A huge effort from everybody, but it’s worth it. 1-0s are sometimes the best ones and successful teams normally have loads of them.”
Hearts host St Mirren in the Premiership on Wednesday (19:45 GMT) before welcome Falkirk in the Scottish Cup on Saturday (20:00).
Dundee are next in action at Kilmarnock earlier that day, also in the Scottish Cup (15:00).
