London Olympics: Day 4 Review: Volleyball Men's competition wide open
Competition for medals in the men's Volleyball competition is heating up after another action-packed day of drama at Earls Court.
Bulgaria v Poland in the men's Volleyball on Day 4
The Bulgaria team and the Poland team shake hands after the men's Volleyball match on Day 4 of the London 2012 Olympic Games at Earls Court.
Olympics Day 4 - Volleyball
Michal Kubiak of Poland tries to spike the ball but it is blocked by Bulgaria during men's Volleyball on Day 4 of the London 2012 Olympic Games at Earls Court.
Poland's suffered a defeat that could cost them dearly as they were beaten by Bulgaria.
Andrea Anastasi's side had been installed as gold medal favourites by some after winning the World League but Bulgaria played them at their own game, hitting them off the court with a simple down-the-middle approach to win 22-25 27-29 25-13 23-25.
Bulgaria are now top of Group A, and they will be favourites to extend their unbeaten record against Australia.
Meanwhile, the United States once again staked their claim as they eased to a second successive win, beating Germany in straight sets.
Alan Knipe's defending champions were written off in the build-up to London 2012, with many believing their much-changed side could not match the achievements of the one that tasted success at Beijing 2008.
But they have a 100 per cent record from their two pool games so far, having beaten Serbia on Sunday and Vital Heynen's side today.
The true tests of their chances are still to come - they have to play arch-rivals Brazil - but their start has been an impressive one.
In the day's other games, Serbia recorded their first win of the tournament as they saw off Tunisia 3-1 and Italy are off and running in Pool A after seeing off a dangerous Argentina side 3-1.
Great Britain lost to Australia, while in the final game of the evening Brazil beat Russia.