Andy Murray knows he will need a big improvement if he is to beat Novak Djokovic tonight and reach the semi-finals of the Toronto Masters.

The British No1 had a 6-2, 0-6, 6-4 win over Stanislas Wawrinka but it was a shaky display, with a mid-match blip seeing him lose seven games in a row.

Third-seed Djokovic, the defending champion, is looking for his sixth successive victory against his fellow 21-year-old while Murray has taken only 10 games in their past three meetings.

"He's obviously, behind Roger Federer and Rafael Nadal, the third best player by a long way," said the eighth seed. "He's playing very well - for me, this is probably his best surface.

"So I have to go out there and play aggressively. I can't afford to make as many unforced errors as I did [yesterday] but I'm playing well and I'm back in the top 10."

Djokovic had less trouble reaching the last eight, recording a 6-4, 6-4 victory over Sweden's Robin Soderling.

Nadal cruised into the next round with a 6-2, 7-6 over Russia's Igor Andreev but the Spaniard and Djokovic are now the only two of the top six seeds remaining.

America's Andy Roddick is out after losing 6-4, 4-6, 6-4 to Croatia's Marin Cilic.

The No6 seed said: "His aggressiveness won him that match. He took it to me a lot more than I took it to him."