Reigning champions USA booked their place in Beijing last night as Canada made history by qualifying for the Olympic Women's Football Tournament for the first time.

The North American duo sealed their places with semi-final victories over Costa Rica and Mexico respectively in the 2008 CONCACAF Women's Olympic Qualifying Tournament, the final of which they will now contest on Saturday evening at 7.30pm local time.

Both last four clashes were played in front of a sell-out 22,800 crowd at Mexico's Estadio Olimpico Benito Juarez, and it was the US who claimed the first of the finals berths with a Natasha Kai-inspired 3-0 win over Costa Rica.

The 24-year-old forward struck twice, on 57 and 89 minutes, as the Americans recovered from an unconvincing first-half showing to cruise into the final, with a 72nd-minute Heather O'Reilly goal sandwiched in between Kai's opportunistic brace.

Of course it was a great feeling when we scored the goals, especially the first one, because then we knew Costa Rica had to attack
USA coach Pia Sundhage

The victory, which maintains the holders' 100 per cent record of qualifying for Olympic finals, was a near-replica of the 2004 preliminary semi-final, which the US won 4-0 in Costa Rica. However, despite the seemingly resounding scoreline, head coach Pia Sundhage criticised her side for showing a lack of intelligence during the goalless first half.

She said: " . But I have to say, we have to be smarter, and I think we were smarter in the second half. They were so tight centrally, so we needed to go wide. We needed to use the flanks better and that's why we changed the system a little bit, so we had Heather O'Reilly and Tobin Heath on each side and I think that changed the game."

Hosts repelled as history is made
While the US were generally expected to see off the Costa Rican challenge, Canada were tipped to find it considerably tougher against a home side spurred on by the noisy backing of a partisan crowd.

However, while the Mexicans had emerged triumphant at the semi-final stage of the 2004 qualifiers, winning 2-1 to deny Canada a spot in Athens, the tables were turned on this occasion thanks to a solitary Melissa Tancredi goal.

I'm very happy for her and very happy with her performance in this tournament
Canada coach Even Pellerud on Melissa Tancredi after another match-winning display from the striker

It was the striker's third match-winning goal in as many games at the CONCACAF competition, and it earned a warm post-match tribute from her coach. " ," said Even Pellerud. "She has suffered from a lot of injuries and her fitness has always been hurt by that, but she has really become a very smart striker and she's getting stronger and fitter and smarter.

Goalkeeper Erin McLeod also kept her third straight clean sheet, leaving Canada as the only team in the tournament not to have conceded a goal, as Pellerud guided the country's women's team to their first-ever Olympic finals.

"The whole back four was excellent, and Erin was very, very focused," Pellerud said. "She played easily her best game in this tournament today. That was a good day to peak."