Aldo de Nigris scored a late consolation for Monterrey in injury-time, but it will be Chelsea that lines up against Corinthians in Sunday's final.
The European champions began the match brightly and David Luiz, who was lining up in the centre of Chelsea's midfield, nearly gave his side an early advantage from 20 yards but he saw his effort drift over the crossbar.
Minutes later, Eden Hazard could have given Chelsea the lead after breaking down the left, but after cutting inside onto his right foot, the Belgian midfielder could only curl the ball past the far post.
Chelsea were playing with increasing fluidity and they scored the goal their creativity deserved on 17 minutes when a Oscar backheel released Ashley Cole into the penalty area and the left-back pulled the ball back for Mata to sweep home from 12 yards.
It took Monterrey 27 minutes to create their first noteworthy opportunity, but when it arrived, De Nigris could only head harmlessly over the crossbar.
The Stamford Bridge outfit had ended the first half in lacklustre fashion but they burst out of the blocks after the break to extend their lead after just 20 seconds of the second half.
Two minutes later, Chelsea all but sealed their place in Sunday's showpiece when a Torres pass across the six-yard box was forced back across goal by Mata, only for Chavez to deflect the ball into his own net.
That goal enabled Chelsea to take their foot off their gas but they were warned not to take their passage to the final for granted when De Nigris forced a save out of Petr Cech.
Frank Lampard was introduced to the fray with just under half an hour remaining as he continued his comeback from a groin injury, and he soon saw a trademark long-range shot go wide of the post.
Monterrey sealed a consolation goal in injury time when Di Nigris broke clear down the right-hand side before curling the ball into the far corner of Cech's net with his left foot.