LONDON >> David McKienzie scored 17 points and the defending champion U.S. men’s volleyball team clinched a top tournament seed at the London Olympics on Monday with a win over Tunisia.

Sean Rooney added 12 points in the 25-15, 25-19, 25-19 win, which set up a quarterfinal against Italy on Wednesday. Tunisia finished the competition at Earls Court without a win.

The United States was coming off a five-set loss to Russia, which ended an 11-match winning streak in Olympic play, dating to the Americans’ undefeated march to the gold medal in the Beijing Games.

The Americans’ preliminary round was highlighted by a four-set victory over top-ranked Brazil, a rematch of the Beijing final.

The fifth-ranked U.S. men weren’t considered among the medal favorites at the London Games, but they claimed silver in the recent World League tournament before opening the Olympics with dominant straight-set victories over Serbia and Germany.

Against No. 20 Tunisia, coach Alan Knipe rested Kaiser High and University of Hawaii alum Clay Stanley and fellow veterans Reid Priddy and David Lee. The team didn’t need them, claiming the first set on Matt Anderson’s spike and cruising the rest of the way. David Smith spiked for match point.

The United States landed in a difficult pool in London with Brazil, Russia, Serbia, Germany and Tunisia. The top four teams, based on a point system, advance to play in the quarterfinals.

The top finishers in each pool face the fourth-place finishers in the opposite pool, while the other matches are determined by drawing lots.

Bulgaria, Poland, Argentina and Italy advanced out of the other pool.

Tsvetan Sokolov scored 21 points in Bulgaria’s straight-set victory over Italy to secure the top seed in its pool.

Todor Aleksiev added 13 in the 32-30, 25-20, 25-19 victory for the surprisingly strong Bulgarians, who dropped only one of five preliminary round matches.

Ivan Zaytsev had 15 points for Italy, which finished the opening round 3-2.

The ninth-ranked Bulgarians came to London in disarray. After the team earned an Olympic berth, the coach and a top player resigned to protest their country’s leadership of the sport. Nine of 12 players are first-time Olympians.

“We have created this really good climate among all the players,” coach Nayden Naydenov said. “That’s why we are playing so well. They are a really good team.”

In the biggest upset Monday, No. 22 Australia beat No. 3 Poland 25-21, 25-22, 18-25, 25-22. Travis Passier’s ace proved the match-winning point, and the Volleyroos earned a standing ovation from the Earls Court crowd.

The loss kept Poland from a top seed.

“We lost control in the beginning, and we were not really fighting,” Poland coach Andrea Anastasi said. “I have no explanation.”

The Volleyroos, making their first-ever appearance in Olympic volleyball, needed winless Britain to defeat Argentina in an afternoon match to advance. But the eighth-ranked Argentineans defeated the hosts 25-18, 25-18, 25-15.

Russia defeated Serbia 25-15, 25-20, 25-17.