Shields rallies to win middleweight quarterfinal

American Claressa Shields, right, lands a punch on Anna Laurell of Sweden. (Scott Heavey/Getty Images)

Middleweight Claressa Shields rallied with a strong fourth round to defeat Anna Laurell of Sweden, 18-14, and advance to the semifinals in the women’s tournament.

Shields fell behind early, trailing 4-2 after the first round, and the bout was tied as 12 after the third round before Shields went on the offensive and outscored Laurell, 6-2.

The women fight four two-minute rounds instead of the three three-minute rounds fought by the men.

Shields will face Marina Volnova of Kazakhstan in a semifinal Wednesday (9:30 a.m. Eastern time).

Also on London 2012 Olympics

U.S. water polo trails entering fourth