US Open Betting: Has 2nd favourite Nadal reached a tipping point in his season?

None of us like admitting we're getting older. The body keeps adding another year to its age every 12 months, but the mind refuses to keep up.

I can never work out, for instance, how I come to have two sons who are in their 30s. As far as I'm concerned I'm still in my 30s too.

Every now and then reality bites, though. Like it did a couple of weeks ago when I got talked into running in the dads' race at my grandson's school sports day. Four of the guys in front of me fell over on the uneven school playing field, but I still finished last.

I suspect the same sort of process is happening to Rafael Nadal, even though this week he could return to the world number one status he last held in July of 2014.

The Spaniard is the 3.85 second favourite for this week's Western and Southern Open in Cincinnati, and if he wins the tournament will take over from injured Andy Murray at the summit of the game.

But in my view it's a bet to lay, and the same goes for his chances in the US Openwhere at 3.95 he's considered the only real threat to 2.92 favourite Roger Federer.

Despite a wonderful first seven months of the season, in which he has won four titles and got to three more finals, you suspect there are the first signs that a career spent twisting and turning, running from one side of the court to the other with his defiant defensive game, is again catching up with him.

Last week he was brushed aside by 18-year-old Denis Shapovalov, who had started the week ranked 143. The teenager has long been recognised as a hugely promising talent but even so it was a seismic result.

Nadal also gave some clues to his thinking when he was asked to talk about the ranking system and offered the suggestion that tennis should follow golf's lead and base it across two years rather than one.

That, he said, would give players more opportunities to build some down time into their schedule rather than continually chase points. "When you are getting older you need to find periods of rest," he explained.

Now Nadal, of course, is still a youngster at 31 compared to 36-year-old Federer who is basking in the glory of his Wimbledon win.

But his style of play takes so much out of the body that as the year goes on it must get harder and harder to stay at the peak fitness he will need to challenge Federer's smoother, more effortless style.

This week will be a big measure of whether the Spaniard can pose a threat in New York, because after a first-round bye a second-round meeting with Richard Gasquet will be tricky. He will have doubts eroding his confidence after the shock defeat by the Canadian youngster.

His mind won't want to admit it, of course. But the body tends to know the truth about the advancing years.