Multiple Grand Slam title winners John McEnroe and Martina Navratilova discuss whether Novak Djokovic is feeling pressure at Roland Garros in his attempt to become the first man since Rod Laver in 1969 to win four straight majors. Djokovic plays Roger Federer in the semifinals on Friday.

"Novak I think is really feeling the pressure like he did last year," said McEnroe in reference to Djokovic coming into his 2011 French Open semifinal against Federer with a 43-match winning streak; he ended up losing the match. "It's impossible not to feel that because he's so close....I have been around enough big occasions, I know that's gotta start to get to you a little. It did obviously when he played [Andreas] Seppi. It was like he really was struggling. Even against Jo [Wilfried Tsonga] it wasn't maybe as sharp as we've seen him. That's not unexpected. Now that he's gotten here, I expect him to play better. Even though he lost to Roger here last year, it's going to be Roger that's going to have to step up and play even quite a bit better in order to win...There's nothing obviously better than the chance of doing something that hasn't been done for 43 years and getting four majors in a row. So that alone makes it almost impossible to play as well as you can, because the pressure alone and the expectation to have to be able to do that and execute it is almost impossible."

While McEnroe won seven majors, he only managed to win Grand Slam singles titles at Wimbledon and the U.S. Open. Navratilova won 18 Grand Slam singles titles across all four majors. She won six straight majors between 1983 and 1984, starting with 1983 Wimbledon. She won her fourth straight crown in  that period by crushing Chris Evert 6-3, 6-1 in the1984 French Open final. Five-time Grand Slam titlist Djokovic is attempting to do much the same.

"Pressure is off him now for sure getting to the semis," she said. "The pressure was on him against Tsonga and he played well enough to win at the end. Played amazingly when his back was to the wall with the match points. The pressure was on him to get to this stage. Now if he loses to one of these guys, it's okay. But different kind of pressure from last year. Last year he comes here unbeaten, and I think that cost him in the semis. I think he was nervous about it. Now he's going to be the four slams in a row, which hasn't been done since '69. As we say, pressure is a privilege, and he earned it. So I think he'll play his best tennis now because the pressure is off. It's going to take an amazing effort from Federer to beat him. But in the finals, I think pressure is off for Djokovic. If he gets there—presuming Nadal wins—he’s playing the best clay-court player ever, so he can go for broke even if it is going for four in a row. But it's amazing, isn't it? I mean, nobody can be counted is as a favorite against Nadal on clay no matter what the ranking is."