Micheel -- who ended Tiger Woods' winning streak Thursday -- opened up a huge advantage on the seventh-ranked Donald, the highest-seeded player remaining, and held off a late charge to win 4 & 2. In Friday's quarterfinals, he led by as much as 7-up on Donald.
No. 9 Colin Montgomerie is the highest-seeded player remaining in the field. Montgomerie, who is also the only former Match Play champion left, knocked off defending champion Michael Campbell, 1-up Friday.
Micheel is the lone American remaining with a chance to become the first U.S. winner since Mark O'Meara beat Woods in 1998.