MILWAUKEE (AP) _ Italy's Andrea Gaudenzi defeated American Jan-Michael Gambill in the opening match of their Davis Cup semifinal this afternoon.

Gambill fell in his Davis Cup debut, losing in four sets, the last two tiebreakers. Gaudenzi won 6-2, 0-6, 7-6 (7-0), 7-6 (7-4) at the Milwaukee Center Arena.

Gambill, who has risen from No. 227 to 50th in the world rankings after reaching the third round of the U.S. Open _ losing to French Open champion Carlos Moya in a fifth-set tiebreaker _ took Jim Courier's place in the draw. Courier is out because of muscle fatigue in his right arm.

Gambill, who hits two-fisted from both the backhand and forehand sides, survived eight match points before succumbing in the second of the tiebreakers.

Todd Martin, the veteran American in Courier's absence, played Davide Sanguinetti in the other singles match on Day 1. They swap opponents Sunday after Martin and Davis Cup rookie Justin Gimelstob take on Gaudenzi and Diego Nargiso in Saturday's doubles match.