Lots has been made about how old the Big Four are on the ATP Tour. Rafael Nadal spoke about the topic recently in an interview this past weekend ahead of the 2017 Rogers Cup. In regard to being "old," it looks like Nadal, at the old age of 31, needed an afternoon nap, as he just wasn't able to bring much energy to his lethargic interview recently with the ATP.

World No. 1 on the line

On Monday the ATP published an interview with Nadal on their YouTube account. In it the Spaniard spoke about the World No. 1 ranking, something that he said would be "special" to have given everything that he has gone through over the last few years.

He was No. 1 most recently in 2013/14 and has had an inconsistent time since then. Certainly, injuries have been a part of that and Nadal referenced them in the interview. A short time after talking about the prospect of getting back to No. 1 Nadal appeared to "swallow" a yawn and then laugh it off.

Nadal certainly won't be bored when his matches start in the Rogers Cup. He will face either Mikhail Youzhny or Borna Coric in the second round after getting a first-round bye. The Spaniard needs to make the semifinals in Montreal this week to claim the top ranking. In order to do that he will need to survive a quarter of the draw that also has Milos Raonic in it. The Canadian's service games will certainly keep you awake.

He has numerous serves and he hits them all well. All of his serves are weapons on the hard court surface. If he and Nadal face one another in the quarters, Nadal will need to crack the biggest serve on tour in order to get to the No. 1 spot.

Watch Nadal's head-fake yawn

Watching the interview, which can be seen below, you could watch the entire clip as it is -- clocking in at just over three minutes in length.

To see the moment when Nadal tries to hide a yawn go to the two-minute mark and watch for about 20 seconds. The inconvenient yawn and comedic moments thereafter take place at about the 2:13 mark in the clip.

Nadal will be contesting his first match on tour since losing in the fourth round of Wimbledon in a thrilling match against Gilles Mueller.

The Spaniard certainly will have shaken off the disappointment of losing that match as he prepares for the North American hard court season. With Montreal, Cincinnati, and the US Open to come, Nadal's main rival at this point for the top spot appears to be Roger Federer. The two players are seeded one and two in Montreal this season.