Murray ready to u-Serb rivals

Viktor Troicki may not have been the one he had in mind when he set about trying to overtake Novak Djokovic as the world's third-best player, but it is the less-heralded son of Belgrade who stands in the Scot's way of the quarter-finals of the Sony Ericsson Open.

"He's a tough player. He's had a couple of good wins here so far, beating David Nalbandian, so if I want to win that one I'll have to play well," he said.

The 23-year-old Troicki took just six games off the British number one in their only previous meeting in Russia last year. But after watching him thrash former world number three Nalbandian in the second round in Florida, Murray is expecting a far stiffer challenge this time around.

"I played him once before in St Petersburg and won comfortably but he's playing better now than he was then," he added. "I'll have to just try to up my game a bit."

Just as in his second-round match against Juan Monaco, Murray put in a patchy display in Monday night's 6-4 6-4 win over 2004 doubles Olympic gold medallist Nicolas Massu.

The Chilean seized the initiative early on before Murray ground his way back into a dominant position - only to then threaten to fritter the win at 5-1 in the second set.

And the Briton admits that as the Masters tournament enters its crucial last few days, he will have to find a level of consistency he has not displayed since returning from a virus in Indian Wells earlier this month.

"You just have to stay focussed. Sometimes when you get a couple of breaks up the adrenaline goes a little bit and you go for shots you shouldn't be going for," he told Sky Sports.

"You need to stay focussed and I did that really well at the start of the year and the end of last year. It's something that I've lost a little bit since I came back, but I'm sure that for the more important matches it will get better."