Max Purcell has had his chances to earn another top-10 scalp in his burgeoning career but the Australian maverick ended up losing two tiebreaks in a close-fought affair with American star Taylor Fritz at the Swiss Indoors.
Purcell saw a 5-1 tiebreak lead and two set points disappear in the opening set of Wednesday's last-32 clash, and then had a comeback repelled in another breaker as he succumbed 7-6 (9-7) 7-6 (7-4) in a two-hour hard-court duel.
In the tournament famed as Roger Federer's home event in Basel, Purcell appeared to have Fritz in trouble when he raced into the lead in the opening tiebreak, perhaps sensing the opportunity of carving out his second triumph over a top-10 opponent in the last two months.
But the 25-year-old Sydneysider, who had beaten Casper Ruud in Cincinnati in August, was pegged back by the American world No.9, who admitted later to feeling fortunate he was let off the hook when the Purcell served up a double fault while leading 5-1 in the breaker.
Purcell still managed to eke out a couple of set points but Fritz emerged the stronger to earn the key breakthrough at the first opportunity.
It looked as if it would be plain sailing for No.3 seed Fritz when he broke for a 5-4 lead.
But at match point down on his rival's serve, Purcell produced some of his best tennis, even coming out on top in one superb marathon 27-stroke rally, to level the set.
In the second tiebreak, though, another double fault let world No.41 Purcell down as it gifted Fritz four more match points and the American wasn't about to waste those as he set up a last-16 contest with Russian qualifier Alexander Shevchenko.
Purcell's departure meant his Davis Cup colleague Alex de Minaur, with whom he's also playing in the doubles in Basel, was the last Australian singles player standing in the two European ATP events this week in Switzerland and Vienna.
De Minaur faces Dutch No.1 Tallon Griekspoor in the last-16 on Thursday, having lost their only match, on grass earlier this year in s'Hertogenbosch.
The reigning Basel champ Felix Auger-Aliassime - who's not had the greatest time since winning this tournament last year - made a fine start to his title defence, defeating Swiss wild card Leandro Riedi 6-3 6-2 to ease into the round of 16.
In the Vienna Open, Ben Shelton, fresh from his maiden ATP triumph in Tokyo at the weekend, was thrown into a difficult opener against Italian star and No.2 seed Jannik Sinner, who prevailed 7-6 (7-2) 7-5 with a magnificent performance featuring 28 winners and only six unforced errors.
Heavyweights Alexander Zverev and top-seeded Daniil Medvedev also progressed, winning in straight sets against Cameron Norrie and Arthur Fils respectively.