Red Diamonds' match winner Alex Schalk scored the winning goal for Ross County in the 2015-16 Scottish League Cup final
Dutch forward Alex Schalk scored the winner for the Asian champions, five minutes after being introduced as a second-half substitute.
Leon captain William Tesillo was dismissed after picking up a second yellow card late on for the Mexican side, who faded after a bright start.
Japan's Urawa take on European champions City on Tuesday.
In Friday's other second-round match African champions Al Ahly won 3-1 against a star-studded Al-Ittihad side that included Karim Benzema, N'Golo Kante and Fabinho. They will now play Brazil's Fluminense in the other semi-final, on Monday.
Benzema missed an opportunity to level for Saudi Pro League side Al-Ittihad before the break when his penalty was saved by Mohamed El Shenawy, after a spot-kick from Ali Maaloul had put Egypt's Al Ahly ahead.
Second-half goals from Hussein El Shahat and Emam Ashour gave Al Ahly a 3-0 lead.
The only disappointment of the evening for Al Ahly was Anthony Modeste's late dismissal before Benzema scrambled home a stoppage-time consolation.
-- Courtesy of BBC Sport