- 2009 champion Andy Murray into last eight after comfortable defeat of Andreas Seppi
- Tomas Berdych defeats Sam Querrey to ensure no American in quarters for first time
- Serena Williams reaches semis after beating Li Na in tough clash
Andy Murray made light work of Italy's Andreas Seppi as the Scot stormed to the quarterfinals of the Miami Masters Tuesday.
The second seed cruised into the last eight after winning 6-2, 6-4, the fifth time in a row the Scot has beaten the world No. 19 in straight sets.
Bidding to win the competition for the first time since 2009, Murray -- who will play Croatia's Marin Cilic in the quarters -- reached last year's final only to lose to Serbia's Novak Djokovic.
Should the U.S. Open champion win this week's event in Key Biscayne, he will replace Roger Federer as the world No. 2.
Earlier in the day, Spain's David Ferrer defeated Japan's Kei Nishikori to set up a quarterfinal clash with Austrian Jurgen Melzer, who beat another Spaniard, Albert Ramos, in three sets.
Fourth seed Tomas Berdych earned a meeting against Frenchman Richard Gasquet after a more comfortable victory -- winning 6-1, 6-1 as the Czech failed to allow Sam Querrey even one break point.
Querrey's defeat meant that an American male had failed to reach the last eight of the Miami event for the first time in the tournament's 28-year history.
There was no such trouble for Serena Williams in the women's event, as the world No. 1 reached the semifinals after seeing off a spirited Li Na of China.
Despite losing her serve three times, Williams beat the fifth seed 6-3, 7-6 (7-5) in a match that lasted just under two hours.
"She has such fight," Williams said of her Chinese opponent, playing her first tournament since damaging an ankle in January. "She never quits and I think we have a lot of that (in common)."
Playing her first tournament since damaging an ankle injury at the Australian Open, Li's one regret was her inability to serve better.
"She's best player in the world," Li said. "If you couldn't hold, she never gives you another chance.
"I still have to see the positives. I played well so I should be try to be ready for clay court season."