The defending champion US men’s volleyball team opened Olympic play Sunday by sweeping Serbia behind Matt Anderson’s 18 points.

Captain Clay Stanley added 13 points in the 25-17, 25-22, 25-21 victory at Earls Court.

The Americans were not considered a favorite despite a silver-medal finish in the recent FIVB World League tournament. But they were formidable against Serbia, which won the Olympic gold in Sydney in 2000 and finished fifth in Beijing in 2008.

Marko Podrascanin had 13 points, including two aces, for the Serbians.

‘‘It was a good match. We fought hard and won in three straight, which is pretty much exactly what our game plan was to do,’’ Anderson said. ‘‘We wanted to serve tough and put a lot of pressure on them, and I think we executed that pretty well.’’

Four years ago, the US men went undefeated in Beijing, upsetting Brazil in the final. That team was coached by Hugh McCutcheon, whose father-in-law was stabbed to death at a Chinese tourist site just before the Opening Ceremonies. The coach left the team for several matches to be with his family.

McCutcheon shifted to the US women’s team following Beijing, and Alan Knipe took a leave of absence as coach of Long Beach State to coach the men for London.

The US is ranked No. 5 by volleyball’s governing body. The team is in a difficult pool in London, joining top-ranked Brazil, perennial powerhouse Russia, Serbia, Germany, and Tunisia. In the other pool are Italy, Poland, Argentina, Bulgaria, Australia, and host Britain.

The US jumped to an 18-7 lead in the first set and the public address announcer proclaimed it an ‘‘absolute mauling.’’ David Lee spiked for set point.

Seventh-ranked Serbia went up, 6-2, in the second set before the Americans rallied. The Serbians managed to hold off the Americans for three set points before a return error ended the set.

David Suxho’s ace made it 15-7 in the third, and the Americans were on their way, drawing chants of ‘‘U-S-A!’’ from the crowd.

‘‘It was a well-played match, and it was probably more the mind-set of the players that got them through,’’ Knipe said. ‘‘We did a really good job to maintain our composure when we were down in the second set.’’

Since volleyball became an Olympic sport in 1964, the US men have won three gold medals — Los Angeles in 1984, Seoul in 1988, and Beijing in 2008. They won the bronze in 1992.

The US will play Germany on Tuesday.

Argentina 3, Australia 0 — Argentine setter Nicolas Uriarte played sparingly during his team’s 25-21, 25-22, 25-20 victory, but it meant a little extra to him — his father, Jon, coaches the Volleyroos of Australia.

The father-son bond was subtle. During pre-match warm-ups, Nicolas Uriarte slightly raised his hand in the direction of Australia’s bench following the customary handshake between the opposing players. When it was over, Jon Uriarte put his arm around his son as they faced the post-match television cameras.

‘‘Volleyball for me in life was a way for me to express myself and be happy. And all of my children love volleyball just in the same way,’’ Jon Uriarte said. ‘‘This, as a father, seeing them be happy, it’s huge.’’

‘‘I don’t know what life could give me next,’’ he said. ‘‘Already, it’s enough.’’

Jon Uriarte, from Buenos Aires, played 11 years for Argentina’s national team and won a bronze medal at the 1988 Seoul Olympics. It is his second stint as Australia’s head coach, sandwiched around coaching Argentine.

Nicolas is a promising 22-year-old setter, voted MVP of the 2009 FIVB Junior World Championship.

Argentina is ranked No. 8 in the world; the Volleyroos are ranked No. 22 in the world.

The pair aren’t the only father-son combination in the Olympic tournament. Brazil’s Bernardo Rezende, known as Bernardinho, coaches his son, setter Bruno Rezende.

But they are used to playing together: Both Rezendes were also at the Beijing Olympics, where Brazil won the silver medal.

Brazil 3, Tunisia 0 — Top-ranked Brazil made an example of 20th-ranked Tunisia, sweeping the match, 25-17, 25-21, 25-18.

Bulgaria 3, Britain 0 — Bulgaria, ranked ninth in the world, survived a bit of a fight from the 92d-ranked hosts, 25-18, 25-20, 26-24.

Poland 3, Italy 1 — In Sunday’s tightest match, No. 3-ranked Poland dropped the first set to the No. 6-ranked Italians before roaring back, 21-25, 25,-20, 25-23, 25-14.

Russia 3, Germany 0 — The second-ranked Russians outlasted the 10th-ranked Germans in a marathon first set, but had little trouble sweeping them away, 31-29, 25-18, 25-17. Russia clinched the first set on a German hitting error.