A frustrated Nick Kyrgios has prevailed over big-serving Ivo Karlovic in three tough sets to progress to the fourth round of the Miami Open.
The Australian was never broken in the 6-4 6-7 (7-4) 7-6 victory at Key Biscayne on Monday (Tuesday AEDT), winning the deciding tie-breaker 7-2.
He won 94 per cent of points on his first serve, but displayed his frustration by banging his racquet into the court or onto his shoe when his Croatian opponent refused to yield in the second set.
The 21-year-old also drew some boos from the crowd when he appeared to reprimand a ball boy for the way the ball was thrown at him.
But Kyrgios, seeded 12th, regained his composure to reach the fourth round of his fourth straight ATP tournament, keeping his 100 per cent winning record over Karlovic from three matches.
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The Canberra-product smoothed things up with the ball boy at the end of the match by giving him his towel.
Kyrgios will next play the winner of eighth-seed David Goffin's clash with Diego Schwartzman for a spot in the quarter-finals.
Meanwhile, Roger Federer moved into the fourth round, beating No.4 seed Juan Martin del Potro 6-3 6-4.
The 35-year-old Federer, who was facing the 29th-seeded del Potro for the first time since 2013, never lost serve and improved to 15-1 this year.
He broke del Potro twice, once in each set, and that was all he needed.
"A good match overall," said Federer, the 2005 and 2006 champion on Key Biscayne.
"I enjoyed it."
Federer next faces 14th-seeded Roberto Bautista Agut, who needed three sets to top American Sam Querrey.
Tenth-seeded Tomas Berdych was another third-round winner, beating Gilles Muller 6-3 6-4, while Frenchman Adrian Mannarino prevailed over Borna Coric of Croatia 6-4 2-6 7-6(7-3).
Also in the fourth round is Stan Wawrinka who beat Tunisian Malek Jaziri 6-3 6-3 and will meet rising star Alexander Zverev, who won an epic encounter against American John Isner.
The German triumphed 6-7 (7-5) 7-6 (9-7) 7-6 (7-5), saving three match points, in a game that went on for two hours and 40 minutes.
