Taylor Fritz missed a golden opportunity to strengthen his bid for the year-end finals as the American crashed out in the second round at the Swiss Indoors on Thursday.
The provisional ninth in the race to the eight-man ATP Finals from November 12 in Turin went down after nearly three hours to qualifier Alexander Shevchenko 6-7 (7), 7-6 (6), 7-6 (5).
The American hit 22 aces but drew a blank on each of his 15 break chances in a disappointing afternoon at the St Jakobshalle.
Fritz is duelling with rival year-end points contenders Casper Ruud and Hubert Hurkacz for a possible spot in Turin, with Basel top seed Holger Rune currently holding down the last of the eight places at the Italian showpiece.
The 83rd-ranked Shevchenko will play the first ATP quarter-final of his career on Friday after his upset effort over the third seed and has assured himself a move up to 63rd in the world.
The outsider saved two match points while closing out victory on his own first chance as Fritz drove a return long over the baseline.
Main photo:-Alexander Shevchenko beating Taylor Fritz in Basel by Swiss Indoors Basel/Antonio Vasquez
