The summer signing from Getafe climbed off the bench late on to net his first goal for Madrid in the 94th minute, earning the Spanish giants a 2-2 draw and preserving coach
That looked set to consign Mourinho to his first Madrid defeat on his return to the San Siro, where he enjoyed tremendous success with previous club Inter Milan, but Leon drilled a low shot through home goalkeeper
Leon was the centre of attention earlier this season after he was surprisingly omitted by Mourinho for the Champions League trip to Auxerre with the coach telling reporters "when he works how I want him to, he will play, and when he doesn't, it will be harder for him to play", but the 23-year-old made headlines for different reasons at the San Siro.
"My goal is an enormous joy because it's given us the point which means we've qualified. We are very happy," Leon said. "We had a very good game until Inzaghi scored his two goals. Then I've managed to score, but the important thing is the team. I think that an away draw and in the San Siro is a good result."
Leon, whose goal was the first scored by a Spaniard under Mourinho this season, added: "We are a team and we all try to do our bit on the pitch. We are happy, although we all wanted to win. The coach is also happy."
Regarding his side's performance, Mourinho said on Telemadrid: "We have qualified and we are almost sure of first place in the group. The players have given everything and if I'm not going away completely happy, neither am I sad with what happened."