The Germany captain has yet to produce the kind of form that made him one of Europe’s top players but Tuesday night’s 79th-minute Champions League strike will help to silence the doubters.

Chelsea had trailed to a Ricardo Quaresma goal at the interval but a dreadful mistake by Porto goalkeeper Helton allowed Arjen Robben to level three minutes after the re-start.

Ballack then dashed Porto’s dreams of putting one over on their old boss Mourinho when he finished off a four-man move with a crisp volley from eight yards, sealing a 2-1 win on the night and a 3-2 aggregate success.

Mourinho said: “I keep saying that criticism doesn’t make me decide to play him.

“I decide in my mind and from the way I analyse the game. I accept, sometimes, opinions from my assistants – nothing else.

“What the crowd thinks does not make me change my mind. But I think the goal is good for him because it put Chelsea in the quarter-finals.

“It is one of those goals that is like a stamp. He put in a great effort to play a good game. He was exactly like the team – didn’t play well in the first half, but played very well in the second half.

“But we are a team and I don’t like individuals to be in front of the team performance.”

Ballack’s strike completed a fine Chelsea comeback after Mourinho had confronted his players during half-time.

The Blues coach urged them to prove they had the bravery to overcome his old club and earn a place in the last eight of the Champions League.

Mourinho’s masterstroke was replacing the ineffective France midfielder Claude Makelele with Mikel John Obi at the interval. The youngster gave Chelsea added impetus in midfield and Porto failed to adapt.

Mourinho declared: “I had a difficult half-time in the way I had to speak with the players because, at that point, we were out of the Champions League.

“Psychologically, I just made the players think a little bit. I told them that, at that moment, we were out of the competition and either we responded to the situation or we were scared of it.

“If we were scared of it, it is goodbye and we are out of the competition. If we enjoy, let’s play 45 minutes and enjoy being under pressure and see if we can cope with it or not. I think the reaction was very positive.

“When you come out and score a goal inside three minutes, it gives you extra confidence. My players showed a very strong mentality.

“But I was happy with the change I made at half-time. Mikel John Obi gave us the dynamic in midfield. After that, the game was intense and Chelsea had a higher intensity because the English league gives us that.”