United laboured a little to a 3-0 victory against the Hatters at Kenilworth Road.
"It was a very tough game," said the Nigerian attacker to manutd.com. “We knew, from the start, that we were coming to play a tough side. We are happy we are going through to the next round - that is the most important thing.
“We've not started the league very well, but we've won today and I think it's a boost for this weekend's game against Brighton. We'll go there and try to win and start the Premier League [again]."
Ighalo felt that Crystal Palace's lengthier pre-season had a big impact on the result at the weekend, but says that the Reds are improving with every passing day.
“We were disappointed at the weekend because we didn't win the game against Crystal Palace," explained the striker. "We only had one week to prepare for that game; I think they had been preparing for four weeks. So it can tell a bit. But, now we've won this game, I think it's a boost for us. It gives us more confidence to go to this weekend's game. Hopefully we'll win this weekend and start on a good note in the Premier League.
“You can see we are getting fitter and everybody's getting the sharpness. Everyone's getting the game-time, getting fitter and fitter in every game. Now we go to the next game and have some minutes again and keep getting better and better."