Saint George were unable to capitalize on their man advantage as they were held to a goalless draw at home to Espérance Sportive de Tunis at Addis Ababa Stadium in Addis Ababa on Tuesday afternoon.
Ghilane Chalali was sent off for a second bookable offence in the 64th minute for the Tunisian giants, but they showed great resilience to win a point in Ethiopia.
The result retains the two point advantage for the two-time champions atop Group C with AS Vita and defending champions Mamelodi Sundowns set to go head-to-head in Kinshasa on Wednesday.
Kidus Giorgis move up to second spot in their group following a second successive stalemate, having also failed to hit the back of the net in a 0-0 draw away to the Brazilians.
Espérance thought they had bagged the winner with seven minutes remaining, but the goal was chalked off due to a handball in the build-up.
In the end, Saint George were left licking their wounds as they failed to make good use of what was a perfect opportunity to ignite their campaign.