Switzerland's Roger Federer beat Argentine Juan Martin Del Potro on Sunday to win the Swiss Indoors and narrow the gap on world number one Rafael Nadal.
Federer's 6-7 (5-7) 6-4 6-3 win moves him within 1,460 points of the Spaniard before next week's Paris Masters, the final regular-season event.
The 36-year-old claimed an eighth crown in Basel and his seventh title of 2017.
Victory for Del Potro would have moved him into the final qualifying place for the ATP finals in London.
Having won in Stockholm last week, the world number 19 was targeting back-to-back titles in Basel but it was not to be for the 29-year-old, who remains one place behind Spain's Pablo Carreno Busta.
Del Potro must reach at least the semi-finals in Paris to claim the final spot.
"It's unbelievable how well Roger is playing," said Del Potro. "I hope to be in such shape when I'm his age. But I doubt I will be."
However, Federer pulled out of next week's Paris Masters following the final to all but end his chances of taking the year-end world number one spot from Rafael Nadal.
