Although Republican presidential hopeful Donald Trump is dominating headlines after the first GOP presidential debate, he was not entirely happy with how the evening went.

The debate's moderator, Fox News host Megyn Kelly, was notable for her willingness to ask Trump challenging questions, including leveling accusations of sexism at the GOP frontrunner: "You've called women you don't like fat pigs, slobs, dogs and disgusting animals," she said, during the debate.

Trump, seemingly unperturbed, responded with a barb directed at his Twitter nemesis and talk show host, Rosie O'Donnell, but, after the event he complained that the questions directed at him were much harder than those aimed at the other candidates.

“The questions to me were far tougher, and that I -- supposedly, according to what everyone’s telling me, I won the debate, according to the call-ins and everything,” Trump told reporters, after the debate, according to Buzzfeed. “But the questions to me were not nice, I didn’t think they were appropriate, and I think Megyn behaved very badly personally.”

He took particular issue with Kelly's probing of Trump's history of sexist remarks, saying it was “unfair,” adding that “the answers were good obviously, because everybody thinks I won.”

Aside from his jibe at O'Donnell, Trump also responded more substantively to Kelly's charges of sexism during the debate, in a way that suggested he saw her comments as personal attacks. 

“Honestly, Megyn, if you don't like it, I'm sorry,” he said. I've been very nice to you, although I could probably maybe not be, based on the way you have treated me. But I wouldn't do that.”

Trump's lawyer Michael Cohen also criticized the questions in a post on Twitter.

Despite his complaints, Trump said he enjoyed the debate. “I had a really great time,” he said, according to Politico. “I thought it was a fantastic debate.”