Hurkacz denies Medvedev world No 1 spot | Kyrgios fined $35,000

Poland's Hubert Hurkacz kept his title defence going at the Miami Open by beating Daniil Medvedev 7-6 6-3 in their quarter-final on Thursday as the Russian fell one win short of reclaiming the world number one ranking.

Hurkacz stormed out of the gate to win the first three games and fended off two break points in the seventh as Medvedev, who appeared unwell at times in the heat, struggled on his first serve and suffered four double faults in the first set.

The Russian attempted a comeback as he fought off two set points to hold serve in the eighth game and broke in the ninth, but the Polish world number 10 kept his nerve in the tiebreak.

In the second set, Hurkacz broke on his sixth attempt in a marathon, 11-minute fifth game as the sweltering temperature seemed to get the better of Medvedev.

Sitting on his bench after the seventh game, the U.S. Open champion removed his sweat-drenched shirt and requested assistance from the physio, complaining of dizziness.

In the following game, Medvedev hunched over momentarily and later glumly dropped his racket to the court after he whacked a backhand return into the net.

"Playing Daniil is always fun but it's super competitive," Hurkacz said in a broadcast interview after the match.

"I was hitting my forehand a little better and I was returning better so that was big for me."

Medvedev needed to reach the semi-finals to retake the world number one spot from Novak Djokovic. The Australian Open finalist claimed the position briefly earlier this year but lost it after a shock third-round loss at Indian Wells.

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Nick Kyrgios has been fined $35,000 for his behaviour during a fourth-round loss to Jannik Sinner at the Miami Open in