An early goal by Jesus Corona and a second-half double courtesy of Cesare Delgado sent the CONCACAF champions through to the semi-final against the European champions on Thursday
The Mexican outfit earned a prestigious clash with European champions Chelsea with a dominant display over the Koreans, who never looked like they were going to match their opponents.
The game immediately started on a high just nine minutes after kick-off. Mexico international Aldo De Nigris crossed from the left and found team-mate Jesus Corona in the penalty area, with the latter easily tapping home from close-range after taking advantage of poor positioning from Ulsan's defence.
The Rayados almost doubled their lead three minutes later, when an unmarked De Nigris headed directly into Kim Young-Kwang's hands from a favorable position.
The Korean goalkeeper was then forced into a difficult save when he palmed away a minacious drive from Cesar Delgado in the 17th minute, and the Mexicans continued to threaten their opponents' rearguard with a quick and energetic display.
In the second half the Asian champions tried to come out from their shell early on with some aerial attempts, but it was Monterrey who again found the back of the net, only for the linesman to cancel out Sergio Perez's header for being offside.
Ulsan's most dangerous weapon was Kim-Shin Wook's height, but the 24-year-old rarely proved to be a handful for the opposing centre-backs as he was often isolated.
The lack of support for Ulsan's strikers was severely punished by Monterrey, who despite lowering their tempo in the second-half, played an effective defending game.
Cesar Delgado opened his account on 77 minutes after a classy combination with Corona and De Nigris, which circumvented Ulsan's opposition and allowed no chance for Kim Young-Kwang.
The second goal blew out Ulsan's hopes of coming back into the match when Delgado completed the brace seven minutes later, firing the ball past Kim after Walter Ayovi's pass from the right.
The 'Gangsters of Asia' found a late consolation through Lee Keun-Ho, with the Asian Footballer of the Year giving Korean supporters something to cheer about on a disappointing afternoon, with an effort from 25 yards that Monterrey goalkeeper Orozco mis-handled.
The K-League side are now set to face the loser of Sunday night's match-up between J-League champions Sanfrecce Hiroshima and African kings Al-Ahly.