Rafael Nadal and Roger Federer team up to give Europe a 9-3 overnight lead over the World going into the final day of the Laver Cup ©Getty Images

Roger Federer and Rafael Nadal teamed up give Team Europe a 9-3 lead over the World Team after the second day of the inaugural Laver Cup in Prague as they beat Sam Querrey and Jack Sock 10-5 in the tie break after winning the first set 6-4 but then losing the second 6-1.

Nick Kyrgios had earlier offered clear evidence that this new event - a tennis version of golf’s Ryder Cup - is no mere exhibition play as he went on a furious rant at the umpire before seeing out a victory over Tomas Berdych that earned the first points of the day for the World team, cutting the European lead to 7-3 at the O2 arena. 

With points for victory being doubled on the second day of competition  - wins on tomorrow’s concluding day will be worth three points - Federer and Nadal took Europe’s overnight lead of 3-1 to 7-1 with respective wins over Querrey and Sock.

Krygios, overseen by the World’s non-playing captain John McEnroe - who was not averse to the odd rant himself in a stellar career - hit a flashpoint when he was a set down and serving at a crucial point in the second.

With the scores locked in games at 5-5, the 22-year-old Australian saved a break point before serving out the game with an ace - or so he thought.

But the umpire called it a let in a decision that left Kyrgios furious.

Nick Krygios starts to
Nick Krygios starts to "lose it" during his singles match against Tomas Berdych but he regained his composure to add the only points for the World Team on day two of the Laver Cup against Europe ©Getty Images

The world number 20 shook his head and walked towards the umpire.

Television cameras heard him question the decision, telling the official: "What? I'm about to lose my s**t if you call that a let."

The crowd let out whistles before the umpire told Kyrgios he was standing by his decision, telling him the net machine had made the decision by alerting him with a beep.

Kyrgios was unimpressed, retorting: "F**k the machine though" before picking up his towel and receiving a few calming words from McEnroe.

Kyrgios let off some steam by hitting a ball into the crowd but eventually held before winning 4-6, 7-6 and 10-6 on the tie-break.

Federer had begun the day by keeping Team Europe - who are being guided by Bjorn Borg - in control of the Cup with a 6-4, 6-2 victory over Querrey.

Nadal, who had lost in the doubles with Berdych on the opening evening, had a far harder job earning his two singles points for Europe as he finally came through 11-9 in the tie break against Sock after a 6-3, 3-6 scoreline.