Andre Villas-Boas said "faith and courage" had enabled his 10-man Shanghai SIPG side to begin their Chinese Super League group campaign with a 1-0 win over FC Seoul on Tuesday.
Hulk gave Shanghai the lead eight minutes into the second half with a spectacular strike into the top corner before He Guan was sent off.
And Dejan Damjanovic saw his penalty saved by goalkeeper Yan Junling as Seoul threatened to level.
"It was a tough game," Villas-Boas said. "You could see the pitch was not in a very good condition and caused problems for both sides.
"Every one of us felt how competitive the match was, especially in the second half when we had one player less, but the team managed to hang in there until the end with faith and courage, and finished with three points.
"This is a crucial away win, and extremely important to our qualification from the group."
He hailed his goalkeeper's crucial intervention, saying: "Yan Junling was able to stop the penalty given in such a stressful situation, and that is because of his training and calmness."