PRAGUE • If anyone was still in any doubt as to the meaning and significance of the Laver Cup, then they need only have watched the latter stages of Sunday's final match between Roger Federer and Nick Kyrgios to realise that this an event that is more than a hit-and-giggle.
In the midst of a deciding match tie-break, it could not have been any more intense inside Prague's O2 Arena, with the 16,700-capacity crowd on the edge of their seats. An anxious Rafael Nadal - team-mate of Federer for a few days rather than his arch-rival - could not keep still on the courtside team couch.
The moment of victory for Europe summed it all up. Nadal charged onto the court and jumped with joy into the arms of Federer, who had saved one match point before prevailing 4-6, 7-6 (8-6), 11-9 in two hours and six minutes. On the opposite side of the net, a devastated Kyrgios was in tears.
There are cynics who will understandably wonder if what they witnessed this past weekend was real.
After all, the Laver Cup is technically an exhibition - it offers no rankings points and has no official tour sanction. This was a contest which was trying to forge a rivalry out of nowhere between teams representing Europe and the rest of the world.
The success of the inaugural Laver Cup depended on the players showing that, deep down, it truly meant more than a regular exhibition. Federer, one of the architects of the event, was satisfied afterwards that this was achieved.
"There is pressure having to prove that it's successful," he said. "The only way it was ever going to be successful is if the players cared, and they did."
The 36-year-old, who has won a record 19 Grand Slam singles titles, an Olympic gold medal and Switzerland's first Davis Cup, described the winning moment as "a feeling that was on the same level as the biggest moments I've had in my career".
There were curious eyes from the numerous organisations, all holding varying shares of power within the sport, watching the action this weekend.
The launch of the event has been seen by figures at the International Tennis Federation as a threat to the Davis Cup, a competition that may have 117 years of history, but struggles to attract the top players to compete on a regular basis due to its demanding format.
What particularly impressed was the innovation used to show tennis in a fresh light. Viewers at home could hear John McEnroe, the World captain, giving Kyrgios candid pep talks and see Nadal rushing to the courtside bench to give Federer some words of advice.
"Just to be a bit more aggressive," Nadal told Sky Sports when asked what he said to Federer. "He is playing great, and controlling the points from the baseline.
"But we thought that he could be a bit more aggressive on the forehand and Roger agreed."
The scoring system also ensured that the tie was still very much alive on the final day, with one point for a win on Friday, two points on Saturday and three points on Sunday. Europe ended up as 15-9 winners.
"You've got to be an idiot if you don't think this is something that could be great for tennis," said former world No. 1 McEnroe. "I can't imagine there's a player that played - or didn't play, for that matter, and watched it - who wouldn't think this is something we should be supporting."
THE TIMES, LONDON, NYTIMES