Dylan Armstrong won Canada's first medal of the 2011 world track and field championships on Friday, taking silver in the men's shot put in South Korea.

Armstrong's best throw of 21.64 metres had him in the lead with just one other thrower left in the final round. But Germany's David Storl bettered it with a personal best of 21.78m to move into top spot.

Armstrong had a chance to take back the gold with the final toss of the competition, but he was called for a foul (the shot landed well short anyway), giving the victory to Storl.

Medal Standings The leading countries by total through Day 7: Rank Country G S B Total 1 United States 9 5 2 16 2 Russia 6 4 5 15 3 Kenya 5 4 3 12 T4 Germany 2 2 1 5 T4 Jamaica 2 2 1 5 T4 Great Britain 1 3 1 5 T20 CANADA 0 1 0 1

"I was definitely gassed by that point," Armstrong, who threw six times, said later on a conference call with Canadian reporters. "The humidity was really taking a toll, especially on the bigger guys.

"But it's awesome. I'm on the podium and that's all that matters."

Andrei Mikhnevich of Belarus claimed the bronze with a mark of 21.40m in the Day 7 evening session at Daegu Stadium, where officials recorded the temperature at 27 C with 64 per cent humidity.

Armstrong's silver is the first medal ever won by a Canadian in a throwing competition at the world track and field championships, which have been held 13 times since their inception in 1983.

It's also the first medal at a global senior international competition for Armstrong, who missed the bronze medal at the Beijing Olympics by one centimetre. Armstrong won gold at last year's Commonwealth Games and at the 2007 Pan American Games. He was a silver medallist in the hammer throw at the junior world championships in 2000.

The 30-year-old from Kamloops, B.C., was considered Canada's best, and perhaps only, hope for a medal at this year's worlds in Daegu. He's the world leader this year with a throw of 22.21 at the Canadian championships in June.

Three Canadian 100m hurdlers, including former world champion Perdita Felicien, advanced to the women's semifinals earlier in the day.