It was end-to-end stuff for the full 90 on Wearside.
Mourinho was delighted with the way his side played going forward, but disappointed with some of the defending with all the Black Cats' goals coming from set-pieces.
He said: "We played a phenomenal game, the best game away from home. It was top quality, building up well, great creativity with the three attacking players behind Fernando [Torres] - Mata, Willian and Eden - beautiful goals. Even the fourth was a nice counter-attack situation.
"The game is about that, but it is also about basic things and we failed in the basic things of the game. The most basic thing is to defend set-pieces.
"It was a very good performance. Even defensively, I think we did well, but the set-pieces... In the last six minutes of extra time, if they had two more corners, they would have won 5-4.
"When you play so well, you have to win comfortably and not give a headache to the manager in the last six minutes."
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