Nick Kyrgios and Alex De Minaur collapsed to the court after clinching a 2-1 quarter-final victory for Australia that knocked Great Britain out of the inaugural ATP Cup.
The duo held each other on the ground after winning the final point in the doubles against Jamie Murray and Joe Salisbury in Sydney.
It had been a thrilling match, Murray and Salisbury winning the first set 6-3 before losing the second 6-3 and taking the crowd at Ken Rosewall Arena to a tie-break.
Kyrgios served at 17-16 and Salisbury returned long, but before the win could be given the British challenged whether the world number 29's serve had gone in.
The review showed it clearly had and the unlikely pair fell to the ground.
The Australian duo were a surprise choice, team captain Lleyton Hewitt sending them in at the last minute ahead of Chris Guccione and John Peers.
"It was unreal," Kyrgios said on the ATP Cup website. "The adrenaline has kind of worn off and I'm exhausted after that match. It was awesome.
"Today was probably one of the best moments in my career, definitely. Just making it through to the semi-final, the first-ever ATP Cup in that type of fashion, was pretty special... we genuinely care for each other, and (our team-mates) were genuinely just so ecstatic to get through."
Speaking on court in the immediate aftermath, Kyrgios had joked he would need "a bit of red wine" to unwind after such a dramatic encounter.
"That was probably the most stressful tiebreak I've ever played in my life," the 24-year-old said.
Britain had four match points of their own, but Murray was left to rue a missed backhander on top of the net.
"I missed that shot basically on top of the net, which was ridiculous," he said. "We hung in and we did well. We just couldn't quite get the last point. Yeah, we lost. I mean, that was it."
Earlier, Cameron Norrie lost the first match of the day 6-2 6-2 to Kyrgios, before Dan Evans continued his strong return to the game with a hard-fought 7-6 4-6 7-6 (2) win over De Minaur which lasted over three hours.
The Australian survived four match points to force a tie-break, before Evans proved too strong on his own serve and the Australian returned wide to end proceedings.
"That's why I play sport is for occasions like that. I enjoyed it," Evans said. "It hurt a bit, but I enjoyed every minute of it out there."
Australia now progress to the semi-finals, where they will meet either Belgium or Spain.