Monterrey will meet Chelsea and Al Ahly faces Corinthians in the FIFA Club World Cup semifinals in Japan.
Monterrey and Al Ahly booked their spots in the semi-finals of the FIFA Club World Cup in Japan on Sunday.
Despite sitting seventh domestically in Mexico and without a win in five matches, Monterrey were far too good for K-League outfit Ulsan, winning 3-1 at Toyota Stadium.
The CONCACAF Champions League winners will meet English giants Chelsea - winners of the UEFA Champions League - on Thursday as a reward for their victory.
It took Monterrey just nine minutes to open the scoring through Jesus Corona, who tapped home a superb cross from Mexican international Aldo De Nigris.
De Nigris should have doubled Monterrey's lead three minutes later but his header was straight at Ulsan goalkeeper Kim Young-Kwang, who made a superb save to deny Cesar Delgado moments later.
It was all Monterrey though and they found the back of the net early in the second half, only for Sergio Perez's header to be ruled out for offside.
The all-important second goal finally came on 77 minutes when Argentine Cesar Delgado finished a neat move that involved Corona and De Nigris.
Delgado completed his brace seven minutes later, firing the ball past Kim after Walter Ayovi's pass found him in space.
Ulsan managed a late consolation, with Asian Footballer of the Year Lee Keun-Ho netting a 25-yard effort.
But it mattered little as Monterrey booked a clash against the European champions.
In the other quarter-final match, Egyptian side Al Ahly surprised J.League champions Sanfrecce Hiroshima 2-1.
African champions Al Ahly took the lead after just 15 minutes when Al Sayed Hamdy found the back of the net.
Hisato Sato pulled back an equaliser for the Japanese outfit 13 minutes before the break to ensure both sides entered half-time with proceedings level.
It was Mohamed Abo Trika who bagged the winner, with the midfielder's 57th-minute strike enough to separate the two sides