The Bluebirds are through to the second round of the competition after seeing off Pompey 2-1 after extra time on Tuesday evening.
Afterwards, Warnock was asked if he plans to add to his squad before the transfer window closes and, while he admits there's always room for a couple of new signings, he is satisfied with the players at his disposal.
"The squad is as good as it can be really. I think we’re competitive. Everyone wants another one or two players but we have to keep going."
Cardiff had to come from behind to beat the League One side thanks to Greg Halford's extra-time goal after winger Nathaniel Mendez-Laing had cancelled out
captain Sean Morrison's own goal.
Warnock was pleased with his players' fitness but admitted they had been poor in the first half of normal time.
He added: "I had a fair few words at half-time. "Second half and extra time we were super, fitness wise, although then (we were) missing great chances to win the game.
"All credit to them persevering. I thought the fitness once again showed through. I thought that at Burton on Saturday."