Murray firing on all cylinders

MELBOURNE, Australia -- Here's a look at some notable matches on Day 6 of the Australian Open:

Andy Murray (4) vs. Jurgen Melzer (31): Murray truly burst onto the tennis scene by marching to the U.S. Open final in September, and with a little better scheduling, might have opened his Grand Slam account in New York. Along the way the 21-year-old dismantled a fatigued Rafael Nadal in the semifinals and knocked off one of the hottest players at the time, Argentine Juan Martin Del Potro, in the quarters.

The versatile Scot almost didn't get past the third round in Flushing, courtesy of Melzer, a dangerous, watchable (the females will verify that) lefty from Austria. Melzer led Murray by two sets and was a whisker away from wrapping things up in a third-set tiebreaker -- two points away, to be precise -- before the fourth seed produced a rally we're seeing more and more of. Wilting physically, Melzer crumbled in the fifth set, and Murray turned Popeye for the second time in two months, flexing his biceps at the end to display his fitness.

Less than three weeks later, the duo met again, this time in the Davis Cup world group playoffs at Wimbledon. Melzer turned up the heat, saying that carrying the entire load for Great Britain in the series would take its toll on his opponent. Murray was ticked and took Melzer out in four sets. Austria eventually advanced thanks to the habitual ineptness of Great Britain's No. 2.

"Melzer is very tough if he plays well," Murray said after an easy second-round win over Spaniard Marcel Granollers, a rival since their junior days. "The U.S. Open was, I think, mentally, quite a tough one for him. He told me after the match he played one of his best matches. Obviously I still came through that one."

Melzer, who toppled rising Japanese star Kei Nishikori in the first round, which some would call an upset, insists there's no bad blood heading into Saturday's meeting, their fourth overall. Murray is 3-0.

"I have absolutely no problem with him," Melzer said. "We have already chatted here. He is a cool guy. To me he is the No. 1 contender to win this title, but I outplayed him for three sets at the U.S. Open, and it's not easy to do that."

Since Flushing Meadows, Murray's game has elevated even further, so Melzer has to hope his opponent misfires.

Prediction: Murray in four.

Richard Gasquet (24) vs. Fernando Gonzalez (13): Expect tons of glittering winners -- and momentum changes -- between Gasquet and Gonzalez, two of the most talented, mentally shaky players around. Gasquet, slipping to fourth on the depth chart in France, at least entered the Australian Open with momentum, topping countrymen Gilles Simon and Jo-Wilfried Tsonga en route to semifinals in Sydney and Brisbane, respectively. Gonzalez had less prep, nevertheless ousting home hope Lleyton Hewitt in the first round.

Prediction: Gonzalez in five.

Elena Dementieva (4) vs. Samantha Stosur: The unassuming Dementieva is riding a 12-match winning streak, boosted by ample offseason training in the U.S. Those double faults, an issue for the longest time, ceased last year, though she has produced 14 in two matches so far. Stosur is dangerous, and playing at home with nothing to lose she should be even more of a threat.

Prediction: Dementieva in three.

Ravi Ubha is a frequent contributor to ESPN.com.