Mexico lead Senegal 1-0 at the interval of their Olympic quarter-final at Wembley Stadium.
It was Mexico who started the better and they might have taken the lead inside three minutes when Marco Fabian struck an effort from outside the box, but he rattled the crossbar.
Both sides flooded forward in a lively opening to proceedings, with Moussa Konate and Cheikhou Kouyate attempting to link up deep into the Mexico half.
Mexico had the lead after 10 minutes, however, when Jorge Enriquez met a Giovani dos Santos cross to send his header into the back of the net.
Senegal responded well and so nearly levelled when Konate struck from distance, but Jose Corona pushed the ball to safety.
Senegal again came close after 21 minutes when Saliou Ciss searched out Konate in the area, but the striker just could not gather and Mexico forced the ball to safety.
Senegal continued to force chances, but Corona produced a fine save to deny a Konate header from close range.
Both sides had chances in the latter stages of the first period - with Oribe Peralta heading just wide for Mexico - but Enriquez's effort remained the only goal of the half.
