By virtue of Nadal's withdrawal, Novak Djokovic has mathematically clinched the year-end No. 1 ranking.
Nadal is five years younger then Federer, but his all encompassing physical style of play has always put demands on him physically. Roger Federer has a big serve too'. The world No. 2 has not played since retiring from his U.S. Open semifinal showdown against Juan Martin Del Potro because of a knee issue.
Rafael Nadal has once again been forced to withdraw from a tournament this week, missing the ATP Finals to continue a worrying trend for the Spaniard in hard-court tournaments.
The beaten finalist at Melbourne Park in 2017, Nadal saw his Australian Open campaign end in painful fashion this January.
The 22-year-old Khachanov defeated the 31-year-old Djokovic 7-5, 6-4, denying the Serbian superstar a chance to win his fourth tournament title in a row. But he competed in only three events after the French Open in June.
He should be feeling pretty good about his game right now and would be looking forward to reversing the results of his last year's showing in London where he was unable to win a match.
However, despite his achievements, Djokovic appears doomed never to be held in the same warm esteem as Federer and Nadal. However, the two men have excelled on the ATP circuit this year.
Nadal lost only four matches this year out of 49.
Despite the doubts, the plaudits were generous on Monday. The Greek was unable to go all the way, losing to Rafael Nadal in the title match but achieving something that has not been seen that often at the events of the premium ATP series.
Nine members of family killed in Sicily flooding
His wife, two other children, his parents, brother, and sister, his nephew and the boy's grandmother all died, he said. Northern Italy was battered by other storms earlier in the week, killing at least 15 people.