A Syrian athlete was expelled from the Olympics on Saturday after testing positive for a banned substance, taking the gloss off a golden day at the Games when Usain Bolt returns to action and Mexico stunned Brazilto win the men’s football final 2-1.

Ghfran Almouhamad, who competed in the women’s 400 metres hurdles, was the 11th athlete to be thrown out since the start of the Olympic period which began on July 16.

Politics also crashed the party on the penultimate day of the Games when the International Olympic Committee (IOC) called for a South Korean football player to be banned from a medal ceremony after he held up a poster referring to his country’s long-running territorial dispute with Japan.

The incidents only proved a brief distraction from the sporting action, with Mexico surprising everyone by taking their first gold and extending five-time World Cup winners Brazil’s long wait for their first Olympic title.

Oribe Peralta put Mexico ahead after just 28 seconds and added their second in the 75th minute with a header before Hulk replied for Brazil in stoppage time in front of a London Games record of 86,162 fans at Wembley Stadium.

At the main Olympic Stadium, the athletics competition winds up with a men’s 4×100 metre sprint featuring Bolt and fellow Jamaican speedsters who will chase victory and a possible world record.

Local hero Mo Farah, who earned one of the loudest roars of the Olympics when he triumphed before 80,000 people last week in the 10,000, aims to add to his trophy cabinet on the penultimate day of the Games in the 5,000.

PARTY, PARTY, PARTY

Organisers will then have less than 24 hours to prepare the arena for the closing ceremony on Sunday, which artistic director Kim Gavin said would be a celebration of British pop music from the last 50 years.

The Spice Girls, One Direction, George Michael and The Who are expected to perform as London prepares to bid goodbye to what the Guardian newspaper dubbed the “feelgood Games”.

Games chief Sebastian Coe declined to compare London with other Olympics, but said simply: “I’m pretty pleased with the way we’ve delivered.”

“Party, party, party,” he told a news briefing when asked to describe the closing concert ending a drama-filled few weeks.

As well as a “hit list” of more than 30 popular songs, it will feature thousands of athletes and performing volunteers as well as a section devoted to the next summer Olympic hosts, Rio de Janeiro.

“I think it’s a gift that we’ve got Rio next because their eight minutes is so wonderful and really full of that samba beat,” Gavin said of the 2016 hosts. “It’s really creative and very cultural and feels really great.”

The sport was far from over, however, with 32 gold medals, the most of any day, decided on Saturday.

WORLD RECORD?

The sprint relay gives 100 and 200 champion Bolt the chance to better Jamaica’s world record of 37.04 seconds set in last year’s world championships and win his sixth sprint gold in two Olympics.

If Jamaica’s relay squad wants inspiration, it need look no further than the United States. women’s 4×100 quartet who left their Jamaican rivals trailing on Friday and took more than half a second off a record set by East Germany in 1985.

The U.S. men look certain to push Jamaica all the way on Saturday after running 37.38 seconds in their semi-final, the third fastest time ever, while resting two of their best racers.

Jamaica, resting Bolt, were only 0.01 seconds slower.

Farah is world champion in the 5,000 but looked tired in the heats and may find that challengers such as Ethiopians Dejen Gebremeskel and Hagos Gebrhiwet, Kenya’s Isiah Kiplangat Koech and American Bernard Lagat have fresher legs.

Dubbed “Usain Bolt on water”, Britain’s Ed McKeever won the men’s K1 200 canoeing gold, the first to be awarded in the new shorter and more explosive Olympic distance.

That took the hosts to 26 gold medals, comfortably beating their Beijing tally of 19 and the highest in over a century. It puts them third in the overall medals table, which the United States top with 41 to China‘s 37.

DOPING SHADOW

Almouhamad’s ejection follows a Friday where two former dopers won gold.

Asli Cakir Alptekin, who served a two-year ban for doping from 2004, led a Turkish 1-2 in the women’s 1,500, a distance riddled with drugs in recent years.

Russia‘s Tatyana Lysenko, who watched the 2008 Olympics on TV while serving a two-year doping ban, won the women’s hammer.

Also appearing in the men’s 4×100 relay semi-finals were American Justin Gatlin and Briton Dwain Chambers, both time-served drugs cheats.

Saturday’s men’s 50km walk was missing defending champion Alex Schwazer of Italy, excluded from the Games for using the blood-boosting erythropoietin (EPO).

The race was won by Russia’s Sergey Kirdyapkin, who set an Olympic record of three hours 35 minutes and 59 seconds.

(Reporting by the Reuters Olympic team)