Murray's fortitude is as strong as his forehand

Andy Murray poses for pictures after winning in the Paris Masters tennis tournament men's singles final on Nov 6, 2016. [Photo/Agencies]

For each top athlete, there's a word.

For Usain Bolt, it would have to be speed. For soccer's Lionel Messi: balance. For swimmer Michael Phelps: buoyant.

But for the new king of men's tennis, Andy Murray, a quality both mental and physical springs to mind: fortitude.

Meanies would argue that Murray has taken over the No 1 ranking this week - the first Briton to reach the summit - only because the three players who were better than him for so long finally vacated it - the tennis equivalent of John, Paul and George giving Ringo a rare opportunity to sing.

And there is a modicum of truth in that.

Roger Federer, the 17-time major champion who this week dropped out of the top 10 for the first time since Oct 2002, long had the measure of Murray, beating him in three Grand Slam finals, but is now a largely spent force at age 35.

Rafael Nadal's creaky body is paying the bill for his brand of nitro-power tennis that won him 14 major titles and the top ranking for a total of 141 weeks to July 2014.

The 30-year-old hasn't won a major since then, or even made a semifinal, and has endured injuries to both wrists. But his career Grand Slam record against Murray is unequivocal: seven wins in nine encounters, with the last defeat way back at the 2010 Australian Open.

And the top dog Murray toppled, the now No 2-ranked Novak Djokovic, won five of his 12 major titles by beating the Scot in the final.

If Djokovic can regroup, rethink and remotivate himself with new targets after completing his career grand slam this year and then suffering a dip, leaving the door ajar for Murray, the Briton's reign as No 1 could be short.

The top ranking, then, doesn't change the fact that Murray is still "only," a word that seems uncharitable in the circumstances, the fourth-best player in what has been modern tennis' toughest era.

But Murray might well be the most stubborn, the era's paragon of perseverance. Being the fourth member of the Big Four for so long could have broken players with less heart. He first got to No 2 more than seven years ago and spent a total of 76 weeks there. That's a long time to be waiting in the wings.