Andy Murray appeared to be following the advice of former coach Brad Gilbert, whose autobiography was titled Winning Ugly, as he reached the fourth round of the Sony Ericsson Open in Miami last night.

The British No1 defeated Chile's Nicolas Massu 6-4, 6-4 with a display that despite lacking top quality proved effective.

Murray said: "He started very well, hitting the ball really hard with his forehand. But after 3-0 in the first set I played really well until 5-1 in the second, when I completely lost concentration and it ended up being a bit more of a battle than it needed to be.

"I missed a lot of first serves early on and it was giving him a lot of chances to get into the point."

The world No4 will now face Victor Troikoi who beat the Serb Bjorn Phau 6-4, 6-3 .

Top seed Rafael Nadal saw off Portugal's Frederico Gil 7-5, 6-3 but, like Murray, the Spaniard was nowhere near his best.

"I think I didn't play well, I didn't play very good tennis or feel very well on court," said Nadal. "I missed a lot of first serves early on and it was giving him a lot of chances to get into the point."

Fifth seed Venus Williams beat 10th seed Agnieszka Radwanska 4-6, 6-1 6-4.

while her sister, world No1 Serena Williams, also toiled before beating China's Zheng Jie 7-5, 5-7, 6-3.