A sell-out crowd of 42,000 is expected to pack Monterrey's University Stadium as Tigres begin their final push to become the first ever team from Mexico to lift South American club football's most prestigious title.
Tigres will be chasing a convincing first leg win to take to Buenos Aires for the return leg on August 5 as they aim to deny River a third victory in the Libertadores after wins in 1986 and 1996.
Mexican football is currently riding high after the success of the national team in the Gold Cup on Sunday, where they defeated Jamaica in the final in Philadelphia.
Tigres have grown in strength this season, bolstered by the high-calibre signing of French international striker Andre-Pierre Gignac from Marseille earlier this year.
They have already met River in the group stage this year, drawing 1-1 in Buenos Aires and 2-2 in Monterrey.
"We have great respect for our opponents but we also have great confidence and belief in our ability to do well," River's veteran Argentine international Javier Saviola said after arriving in Monterrey on Monday.
The former Barcelona and Real Madrid player is one of River's main attacking weapons, alongside Uruguayan striker Rodrigo Mora.
Tigres meanwhile are determined to give themselves a lead to take back to Buenos Aires next week.
"It's going to be difficult in Argentina, everything will be against us," said Tigres midfielder Jurgen Damm.
"The important thing for us is to try and have a lead to defend, either one or two goals."
Damm, who is of German descent, is one of several players signed by Tigres this year as they attempt to claim their place in history.
The 22-year-old joined the club last month in an $8 million deal despite reported interest from Serie A side AS Roma.
Gignac, however, has been Tigres' star acquisition, excelling in a 3-1 semi-final second leg victory over Internacional of Brazil last week to help propel the Mexicans into the final.
River meanwhile have been forced to restructure their attack after the departure of Colombian international striker Teofilo Gutierrez, who abruptly left earlier this month after signing for Portuguese giants Sporting Lisbon.