Andy Murray usually avoids reading social media during tournaments, but he wasted no time issuing a scathing tweet at the Australian Open this week about those who've called him a "drama queen" in the past.

And after beating Joao Sousa on Friday to book a spot in the fourth round against Grigor Dimitrov, Murray didn't temper his anger one bit.

Murray said that when he suffered cramps during a match against Robin Haase on a hot, humid day at the U.S. Open last year, he was criticized for being dramatic and in need of a psychologist.

When Rafael Nadal was similarly battling cramps against Tim Smyczek at Melbourne Park on Wednesday night, however, Murray said the Spaniard was praised for playing through the pain.

"Clearly Rafa was struggling pretty badly. It was a great effort to come through it, which rightly is what everyone was saying. But that certainly wasn't the case at the U.S. Open when I was in a similar state," he said. "And I just don't understand why that would be the case.

"I was in quite a lot of pain in that match (in New York). Being told that I need to see a psychologist because of it I felt was a little bit unfair. I didn't hear anyone calling for Rafa to see a psychologist the other night."

In his tweet on Thursday, Murray said after his U.S. Open win, he was called "drama queen, unfit, needs to see a shrink, faker."

It's not the first time Murray has been criticized for his on-court demeanor. Former Wimbledon champion Virginia Wade called him a "drama queen" at the 2012 French Open when he overcame back spasms to beat Jarkko Nieminen in the second round.

Murray was certainly drama-free in his third-round win over Sousa on Friday, comfortably beating the Portuguese player 6-1, 6-1, 7-5.

The three-time Australian Open finalist has yet to drop a set in three matches at Melbourne Park. He's also yet to face an opponent ranked in the top 50.

He'll likely be tested more in his next match against No. 10-seeded Dimitrov, who overcame an inspired Marcos Baghdatis — and a stadium filled with chanting, singing Greek and Cypriot fans — to advance to fourth round Friday.

Murray holds a 4-2 advantage in their head-to-head record, but Dimitrov has won two of the last three, including in straight sets in the quarterfinals of Wimbledon last year.

Dimitrov is expecting to see a much more competitive Murray than the one he beat handily at the All England Club.

"I think you hardly ever see like top players to feel really flat early on in the match. I think it's a different scenario this time. I think he has a lot to look forward to," he said.

"In the same time, I'm feeling really ready, and I like my chances every time I go out on the court. So I think it's going to be a great matchup."

As for Murray, his relatively quick matches this week have left him feeling fresh and ready for the challenge.

"You know, he's one of the young guys trying to make a breakthrough, so he'll be motivated," he said.