Lionel Messi, centre, makes his mark with the opening goal [AFP]

Diego and Rafinha helped Brazil to a 1-0 win over Belgium, and Barcelona's
Lionel Messi starred in 2004 champion Argentina's 1-0 victory against Ivory Coast despite a Court of Arbitration for Sport ruling in favour of their European clubs that could have prevented them playing.

Barcelona and German clubs Werder Bremen and Schalke, where Diego and Rafinha are contracted, won a CAS decision that clubs should not be forced to make players eligible for the Olympic tournament.

The German clubs later allowed their players to stay with the Brazil squad.

Argentina coach Sergio Batista said Messi wanted to stay in China, pressuring Barcelona into releasing him for the tournament.

There were huge cheers from both the small contingent of Argentina fans at the Shanghai Olympic Stadium and the many thousands of Chinese spectators when 21-year-old Messi ran out for the warmup 40 minutes before kickoff against the Ivory Coast.

Always a man for the moment, Messi scored on his long-awaited Olympic debut to inspire Argentina to a 2-1 victory over the Ivory Coast.

Almost pulled out of the competition by FC Barcelona, Messi scored in the 43rd minute Thursday at the Shanghai Olympic Stadium to give Argentina the lead.

Sekou Cisse equalised with a powerful header in the 52nd.

But Messi's shot set up the winner in the 85th, Lautaro Acosta turning the ball home after the Barcelona star's shot had been blocked by the goalkeeper.

Brazil start with a victory [AFP]

In Group C, Hernanes scored in the 79th minute to begin Brazil's quest for a first Olympic gold in football.

Belgium surprised the more experienced Brazilians by marking well and even threatened them at times in the 60,000-capacity Shenyang Olympic Stadium.

The Brazilians were only able to create more chances in the second half, after
Belgian defender Vincent Kompany received a second yellow card and was ejected in the 72nd minute.

Brazil coach Dunga admitted his lineup had "had difficulties getting past their defensive scheme.''

But "it's always important to get a win in the opener,'' he said.

"We have a game against New Zealand now and we have to focus on that.''

Hosts fightback

Substitute striker Dong Fangzhuo has scored a late equalizer to give host China a 1-1 draw against 10-man New Zealand in its opener at the Olympic football tournament.

Dong's 88th-minute header from near the penalty spot Thursday went over New Zealand goalkeeper Jacob Spoonley and into the far post, delighting the loud home crowd at the nearly packed 60,000-capacity Shenyang Olympic Stadium.

Midfielder Jeremy Brockie had opened the scoring for New Zealand with a right-footer from inside the area in the 53rd minute, completing Craig Henderson's pass over the Chinese defense.

New Zealand played a man down after Steven Old was ejected for a handball that prompted his second yellow card in the 39th minute.

Draws continue

Midfielder George Mandjeck's late equaliser has given Cameroon a 1-1 draw with South Korea in their opening football match at the Beijing Olympics.

Both teams created a host of scoring opportunities in the physical, seesaw game until Cameroon defender Paul Bebey fouled Park Chu-young.

From the ensuing free kick, Park hit a low, spinning ball that bounced once, slipping by onrushing Kim Don-jin and past Cameroon keeper Amour Tignyemb.

But Mandjeck, who replaced Alain Olle in the 64th minute, equalised nine minutes before full time.

Frank Songoo crossed to Gustave Bebbe in the box, who turned and dropped the ball to Mandjeck to finish.

Jeremy Brockie, right, celebrates New Zealand's opener [AFP]

Nigeria has held the gold-medal favorite Netherlands to a 0-0 draw on, competing evenly with the reigning two-time European under-21 champion in their Olympic opener.

Bolstered by Liverpool forward Ryan Babel and veteran senior national team striker Roy Makaay, the Dutch were picked in many pre-Olympic predictions to challenge Argentina and Brazil for the title.

Using three forwards, the Nigerians created several quality chances Thursday but were lacking a final touch. The Dutch also were dangerous, mostly with Jonathan de Guzman out of midfield.

In other matches, Slobodan Rajkovic equalized with a header from a corner in the 78th minute as Serbia rallied to draw 1-1 with Australia, Italy beat Honduras 3-0 and Stuart Holden ended the United States' three-game scoring drought with a goal in the 47th minute as the Americans beat Japan 1-0 at Tianjin.