Cameron Norrie's hopes of reaching the ATP Tour Finals suffered a blow after he lost to Denmark's Holger Rune in the Stockholm Open quarter-finals.
The British number one is 14th in the world rankings and needs to break into the top seven to qualify for the season-ending tournament in Turin, Italy, next month.
He took the first set but 19-year-old Rune hit back to win 6-7 6-3 6-3.
The teenager will play Australian Alex de Minaur in the semi-finals.
Norrie is already playing catch-up in his quest to reach the ATP Tour Finals after pulling out of tournaments in South Korea and Japan last month.
After battling past Aslan Karatsev in the last 16, Norrie recovered from losing a break in the opening set against Rune to take it on a tie-break.
But the teenager broke serve twice in the second set and then again in the eighth game of the decider to secure his place in the last four.