Australian Open second seed Rafael Nadal might have to review his list of advisers after suffering a serious scare in his third round match at Melbourne Park.

Nadal found himself in deep trouble in the opening set against unseeded Frenchman Gilles Simon who had snatched two service breaks from the Spanish star in the first five games.

Simon was standing at the service line with the set seemingly at his mercy at 5-3 before Nadal had a chance to revise his match plan.

Even then, it didn't rescue the situation entirely with Simon building another three break points at 0.40 on Nadal's serve.

"I start the match without a good tactic, I think" Nadal said.

"I start the match watching the rival, not worried about me."

Nadal finished with a 7-5 6-2 6-3 win and a place in the fourth round.

He might also be looking to sort a few things out with fellow Spanish player David Ferrer.

As players do before meeting little known opponents, Nadal sought some information from Ferrer who had some experience against Simon.

"I thought he would start a little bit more slowly," Nadal said.

"With the ball not very high to his forehand, I thought he will miss a little bit.

"But really, he don't miss, he play forehand return winners.

"Thank you David Ferrer because he gave me this tactic.

"He say me that before the match."

Others to make it into the fourth round included Russian fourth seed Nikolay Davydenko and the player emerging as the "wrecker" of the men's draw, unseeded Frenchman Jo-Wilfried Tsonga.

Playing in only his fifth grand slam, Tsonga had already made his presence felt by knocking out British ninth seed Andy Murray in the first round.

He then beat American Sam Warburg in straight sets before getting rid of Guillermo Garcia-Lopez of Spain.

The test for the Frenchman comes in the next round when he plays eight-seeded countryman Richard Gasquet, a man dubbed by compatriot Fabrice Santoro as "the complete player".

Gasquet had a brief struggle against 31st seed Igor Andreev of Russia before winning the third rounder 6-3 6-2 4-6 6-4.

Davydenko put together his third successive straight-sets win, knocking out Marc Gicquel of France 6-3 6-2 6-3, and will now play fellow Russian Mikhail Youzhny .

For Davydenko, the issue at the Open is as much about recognition as who is on the other side of the net.

For the third time in as many matches he has been dispatched to an outside court, the encounter being played on the Vodafone Arena.

"I try not to think about centre court," he said.

"To come to centre court I need to win four matches."

While the Russian's shot at the organisers is slightly tongue in cheek, he is entitled to considerable respect as one of the most consistent players on tour as well as being one of the best.

Davydenko has reached the quarters at the past three Australian Opens and has made the semis at four other grand slams in the past five years.

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