The Spanish playmaker managed 83 minutes on his first start for two months in the 4-1 Capital One Cup quarter-final win over Hull having come off the bench for 15 minutes on Saturday.
An early goal from Wilfried Bony should have been the platform for a comfortable win but it was not until 19-year-old substitute Kelechi Iheanacho and Kevin de Bruyne (twice) struck in the last 10 minutes that the match was wrapped up before left-back Andrew Robertson scored an even later consolation.
"The most important thing was to qualify for the semi-final but after that it was important for David to have 80 minutes after a long injury," said Pellegrini, who hopes to have some of his big names back at the weekend.
"Kun (Sergio Aguero) has a pain in his heel
He is improving and we will see tomorrow or Thursday if he can play on Saturday.
"Joe Hart can be fit, I am not sure for Saturday but if not for Tuesday (against Borussia Monchengladbach in the Champions League).
"Fernando has a small problem but I think can play on Saturday."
Victory over Hull secured a fourth League Cup semi-final in seven years - having won it for a third time in 2014 - and despite labouring against the Sky Bet Championship side Pellegrini was satisfied.
"I am very pleased because I think it was a difficult game against a good team that is at the top of the table in the Championship," he added.
"More than that we played the third game in less than one week and we have a very good response from the team with different names."
Tigers boss Steve Bruce insists he has no regrets about making seven changes for the club's first League Cup quarter-final.
"The same squad beat Leicester and beat Swansea so I have got to stay true to them if I am going to back my word up and say you are going to play in the cup if you don't play in the league," he said.
"And we lost on Friday (at Derby)
Is it really going to make any difference when you come to Man City?
"Defensively, apart from the goal, I can't remember them creating a chance in the first half even though they had huge possession.
"We needed to stay in the cup tie
Up until 81 minutes, we were in there
Then they punished us."
Source : PA
Source: PA