Shannon MacMillan scored four goals and Kristine Lilly earned her world-record 250th cap on Saturday as the U.S. women's national team blitzed a Canadian B side, 6-1, before 5,693 in the rain at RFK Stadium in Washington.

MacMillan tallied on a terrific free kick from 20 yards in the 16th minute to pull the Americans out of an early deficit, then scored three more in the second half for her third international hat trick and first four-goal game.

Lilly and Julie Foudy also scored for the Americans, who dominated play and outshot their northern neighbors, 20-6. Lilly also had an assist, on MacMillan's fourth goal, and Wagner set up MacMillan's second and third goals.

''I've never done that before,'' said MacMillan of her output. ''But when you're getting passes like the three I got in the second half, if I can't finish those, then I shouldn't be out here.''

University of Portland star Christine Sinclair gave Canada a seventh-minute lead, beating Brandi Chastain to a loft from University of Florida freshman-to-be Melanie Booth and firing it into the left side of the net from about 25 yards.

Canada, which agreed to replace planned opponent Nigeria on Wednesday after the Africans were unable to secure travel visas, informed U.S. Soccer prior to the match that it considered the match a ''B'' game and would not count goals or caps in official totals.

The Canadians were angry that they were unable to bring in four of their five WUSA players. Atlanta (Charmaine Hooper and Sharolta Nonen) and Carolina (Breanna Boyd) wouldn't release their Canadians because the request wasn't made 15 days beforehand, as FIFA requires. The timing of Nigeria's withdrawal from the match made such requests impossible.

Canada did not ask for Boston goalkeeper Karina LeBlanc, instead using SMU standout Erin McLeod, the starter on the Canadian U-19 team that finished second at the FIFA championships last summer.

The Canadians started eight players from the U-19 team, including Sinclair, whose goal would have been her 36th in international play if the Canadian Soccer Association had ruled the game an ''A'' match. Three Canadian starters — Booth, Kara Lang and Brittany Timko — are still in high school.

Other Canadian starters unavailable were former WUSA player Silvana Burtini and Norway-based midfielders Randee Hermus and Kristina Kiss.

San Diego's Christine Latham, who played 57 minutes, was the only WUSA player made available to the Canadians.

Both sides are in preparations for next fall's Women's World Cup.

The match was the opener of a doubleheader at RFK, with Washington and Atlanta playing to a 1-1 WUSA tie in the nightcap.

SATURDAY'S SUMMARY

April 26 at Washington

United States 6 Canada 1. Goals: MacMillan 16, 55, 78, 79, Lilly 33, Foudy 41; Sinclair 7.

United States — Scurry; Sobrero, Fawcett (Slaton, 46), Chastain, Reddick; Foudy (Hucles, 46), MacMillan, Wagner, Lilly; Parlow, Hamm (O'Reilly, 63).

Canada — McLeod; Rustad, Andrews, Booth, Lang; Neil, Moscato (Wilkinson, 68), Timko, Matheson; Sinclair, Latham (Allen, 58).

Yellow cards — Canada: Booth 45.

Referee — Sandra Hunt.

Att. — 5,693.