(Reuters) - Defending champion Andy Murray overpowered Slovakia's Lukas Lacko 6-1 6-2 to reach the quarter-finals of the Japan Open on Wednesday with all the panache of a grand slam winner.

The Olympic gold medalist, playing his first tournament since capturing his first grand slam title at last month's U.S. Open, completed the rout in just 56 minutes.

"I started the match almost perfect," Murray told reporters after stretching his winning streak to nine matches and setting up a quarter-final with Switzerland's Stanislas Wawrinka.

"I only lost a couple of points in the first four or five games," added the Scot. "Once I got the break in the second set I started to play better."

Murray mixed up his game to good effect against Lacko with the centre court roof closed as rain from an approaching typhoon lashed Tokyo Bay.

An array of drop shots and sliced passing shots from mid-court left Lacko shaking his head in disbelief, Murray putting him out of his misery with a sweet drop volley.

Murray, who reached the final of this year's Wimbledon before exacting revenge on Wawrinka's buddy Roger Federer in the Olympic final in London, is not counting his chickens yet.

"He is playing very well just now," Murray said of the seventh-seeded Wawrinka. "I think hard courts are a good surface for him. I expect another tough match."

Wawrinka blew three match points in the second set tiebreaker but came through to beat Frenchman Jeremy Chardy 7-6 6-7 7-5 in two hours, 37 minutes.

"It wasn't easy having (wasted) three match points in the tiebreak," said the 2008 Olympic doubles gold medalist, who served 19 aces.

"You need to be ready to still play the third set and to fight."

Wawrinka praised Murray for breaking his grand slam duck after losing his first four major finals.

"He is playing great," said the Swiss. "He won the Olympics, he won the U.S. Open and he always plays great here. It's going to be tough for sure."

Late starters Serbia's Janko Tipsarevic and Argentine Juan Monaco won their first round matches on Wednesday.

Third seed Janko Tipsarevic, resplendent in a pair of bright orange goggles, beat France's Gilles Simon 4-6 6-3 6-1 to avenge his loss in last week's Bangkok semi-finals.