Nadal retires from Miami Open as Murray progresses

Rafael Nadal was forced to retire from a match for the first time in six years after feeling "dizzy" on a hot and muggy day at the Miami Open in Key Biscayne.

The Spanish number five seed was trailing 2-6, 6-4, 3-0 when he pulled out of his second-round encounter with world number 94 Damir Džumhur of Bosnia and Herzegovina.

Nadal had called for a doctor twice before calling it a day after an hour and 50 minutes.

The 14-time Grand Slam champion last retired from a match in a 2010 Australian Open quarter-final against Britain's Andy Murray, who beat Uzbekistan’s Denis Istomin 6-3, 7-5 today.

"Everything was fine until the end of the first set," said Nadal, who has appeared in the final of the event four times without ever winning.

"Then I started to feel dizzy, not very good.

"It was getting worse and worse.

"Finally, in the second set, I realised that I could not keep playing.

"I wanted to finish the match, but I seriously could not."

Andy Murray began his bid for a third Miami Open title by beating Uzbekistan’s Denis Istomin ©Getty Images

Murray’s victory over Istomin came in his first match since losing to Argentina's Federico Delbonis at the BNP Paribas Open in Indian Wells last week.

The number two seed broke his Uzbek opponent four times as he began his quest for a third Miami title in impressive fashion.

Murray now faces a third round clash with Bulgarian Grigor Dimitrov, who overcame seven double faults to defeat Delbonis 7-6, 4-6, 6-4.

The most notable casualty of the day in the men’s draw was fourth seed Stan Wawrinka as the two-time Grand Slam winning Swiss fell to a 6-4, 6-3 loss at the hands of Russia’s Andrey Kuznetsov.

World number six Kei Nishikori of Japan moved into the third round, dismissing French qualifier Pierre-Hugues Herbert, 6-2, 7-6.

Number nine seed Jo-Wilfried Tsonga of France also advanced, breaking Colombia's Santiago Giraldo four times on his way to a 6-3, 6-1 triumph.