Andre Villas-Boas was pleased with the determination of his Chelsea side after the Blues were, once again, required to end a match without the full compliment of players.
Chelsea had both Jose Bosingwa and Didier Drogba sent off against Queens Park Rangers at the weekend and, on Wednesday night, Ross Turnball saw red against Everton.
Petr Cech, though, replaced Turnball and saved the resulting penalty from Leighton Baines, to ensure Chelsea maintained a one goal advantage.
However, Louis Saha levelled for Everton to take the encounter into extra time, before Royston Drenthe was dismissed for the visitors.
Daniel Sturridge took advantage to provide Chelsea with a path into the last eight of the Carling Cup, and Villas-Boas was delighted with the character of his charges.
"We went down to 10 men, unfortunately, once again and made things even more difficult but we were able to triumph in difficulty and these are good signs for us," said the Chelsea boss.
"We got one of the most difficult draws, Everton away with one of their strongest sides.
"They showed they wanted to go through this phase but we were able, not only to play good football, but show good commitment and desire.
"Everton had the desire and motivation, they were on top and we had to hold on until extra time arrived.
"What satisfies more is the talent came out in this situation and when the numbers got even they found better spaces and we got the goal we wanted."