By Nick Mulvenney
MELBOURNE (Reuters) - Andy Murray doled out another impressive thrashing at the Australian Open Monday but his expected quarter-final showdown with Robin Soderling failed to materialize after Alexandr Dolgopolov shocked the Swede.
Murray and Soderling have been jockeying for fourth place in the world rankings but while the British fifth seed oozed class in his 6-3 6-1 6-1 humbling of Juergen Meltzer, fourth seed Soderling was sent packing 1-6 6-3 6-1 4-6 6-2 by the Ukrainian.
Second seed Vera Zvonareva continued her march through the women's draw with a 6-4 6-1 victory over unseeded Iveta Benesova to set up a last eight meeting with another Czech Petra Kvitova, who ground down Italian Flavia Pennetta 3-6 6-3 6-3.
Losing finalist here last year, Murray had conceded just 16 games in three matches to reach the fourth round and was equally parsimonious in dispatching frustrated Austrian Melzer in just 104 minutes on a sun-baked Rod Laver Arena.
Registering only 10 unforced errors over the match, Murray concluded his victory with a 13th ace to send out a warning to his rivals that he is a serious contender for his first grand slam title.
"I'm not expecting to go through the tournament winning matches like that, with that score line," said Murray. "I'm ready for that mentally when it does get tough ... It's been a very good start, but it's going to get much tougher."
Dolgopolov found Soderling far more accommodating in his battle with the Swede in the opening match on center court, recovering from a poor start to register a well-deserved upset.
Soderling, twice runner up at the French Open, admitted he was nowhere near his best but also paid tribute to the talents of his 22-year-old pony-tailed vanquisher.
"My two biggest weapons are my serve and my forehand. They were not weapons today," said the 26-year-old, who had never previously been beyond the second round at Melbourne Park.
"(But) he's a good player. He has a great backhand and he's moving very well. He's a great counter-puncher. He has a good chance to do really well I think."
Dolgopolov was only the second Ukrainian to reach a grand slam quarter-final after 1999 French Open finalist Andrei Medvedev, who was coached by his father Oleksandr.
"The first set I was struggling, and a break down in the second," said Dolgopolov. "I came back somehow and started to play better and better with every set. I'm really happy I'm through to the quarter-final."
Another young gun's free-wheeling run through the draw ended when seventh seeded David Ferrer patiently saw off Canadian qualifier Milos Raonic 4-6 6-2 6-3 6-4.
Ferrer blunted the 20-year-old's rocket serves to reach the quarter-finals and a meeting with Croatia's Marin Cilic or fellow Spaniard Rafa Nadal.
Zvonareva also started slowly and had to recover from a 4-2 deficit in the first set but soon stepped up her pace to end up a convincing winner over Benesova.
The 26-year-old Muscovite, a tearful loser in the finals of Wimbledon and the U.S. Open last year, sealed the victory on her second match point with a thumping forehand crosscourt winner.
"I learned a lot over the last two grand slams," said Zvonareva. "I think I know myself a little bit better now. Hopefully that experience will help me to play my best tennis when I need it."
Agnieszka Radwanska later brought an end to Peng Shuai's run at the year's first grand slam, edging the unseeded Chinese 7-5 3-6 7-5.
The Pole will meet the winner of the match between three-times U.S. Open champion Kim Clijsters and Ekaterina Makarova in the quarter-finals.
Clijsters, a strong favorite for the women's title, meets Russian Makarova in the final match of the day on Rod Laver Arena after Nadal's fourth round match.
(Editing by Peter Rutherford)