NICK Kyrgios was at his sparkling best - and he needed to be - while booking a semi-final date with Roger Federer at the Miami Open.

The Aussie star met 19-year-old German Alexander Zverev for the second time in his career and maintained his status as the most promising young gun in the game with his second victory, 6-4 6-7 (11-9) 6-3.

After taking 41 minutes to claim the first set, Kyrgios opened the second with one of the most impressive between-the-legs shots of his career.

He followed that with a crowd-pleasing act of chivalry, when he encouraged Zverev to challenge a baseline call, which fell in his opponent's favour.

Kyrgios, perhaps conscious of how often he goes viral for negative moments, responded to the crowd's congratulations by saying: "I want to see that on social media."

Tennis TV obliged and Kyrgios created more Twitter chatter when shortly after he was given a time violation warning by the chair umpire. He replied "yeah, give one to Rafa" - in reference to Spanish star Rafael Nadal's reputation for taking longer than any player on the tour to get through his service games.

Zverev took the second set in a tiebreaker as the two tyros traded blows from the back of the court. The German survived two match points to level the breaker at 6-6, before serving an ace to earn a set point of his own.

Kyrgios responded with his 11th ace of the match and a service winner to gain his third match point, but after taking control of the rally with a backhand down the line, hit a drop shot that bounced far too high to miss his chance.

Two ridiculous backhand lobs - one which left Kyrgios stranded and another which forced him to play a tweener into the net - allowed the world No.20 to level the match at a set apiece.

But consistently doing more running along the baseline appeared to catch up with Zverev in the third as Kyrgios broke in the sixth game on his way to a sensational win.

The Canberra native looms as the main threat to a repeat Federer-Rafael Nadal final, after the two veterans met at Indian Wells.

Kyrgios was scheduled to play Federer in the quarter-finals of the California event but was forced to pull out of their match after suffering a bout of food poisoning.

In Miami, Federer survived a match point in an unusually tight three-set win against a man he usually dominates, Tomas Berdych.

The 6-2 3-6 7-6 (8-6) victory came a day after Nadal booked a semi-final berth against Italian world No.40 Fabio Fognini, who upset Japan's Kei Nishikori.