Ben Shelton relied on his powerful serve to escape a tough opening-round test at the Swiss Indoors Basel, firing 44 aces to defeat Aleksandar Kovacevic in a three-set thriller on Tuesday.
The American, who was the US Open runner-up, needed two hours and 36 minutes to overcome the lucky loser 6-7(4), 7-6(3), 7-6(4). After dropping the opening set, Shelton kept his composure in two closely contested tie-breaks to secure his place in the next round.
Shelton said he had been working on improving the accuracy of his serve, focusing more on hitting specific spots rather than relying solely on power. The adjustment proved effective on Basel's fast indoor courts, helping him avoid an early exit.
He will next face Swiss wild card Jerome Kym, who caused an upset by defeating Arthur Rinderknech in the first round.
While Shelton celebrated his hard-fought victory, the tournament also marked an emotional milestone for Swiss tennis as Stan Wawrinka played the final professional match of his career.
The three-time Grand Slam champion lost 7-5, 7-6(2) to eighth seed Jiri Lehecka in front of his home crowd. Although Wawrinka could not end his career with a victory, the occasion provided a fitting opportunity for fans to recognise his achievements.
A former world No. 3, Wawrinka won 16 tour-level titles, including the Australian Open in 2014, the French Open in 2015 and the US Open in 2016. His powerful one-handed backhand and ability to defeat the world's top players made him one of the most respected competitors of his generation.
Lehecka acknowledged the significance of facing Wawrinka in his final match, paying tribute to a player he had watched and admired while growing up. The Swiss veteran's farewell brought an end to a career spanning more than two decades.
Elsewhere, Rafael Jodar strengthened his bid to qualify for the ATP Finals with a convincing 6-4, 6-2 win over Alejandro Tabilo. The 20-year-old Spaniard entered the tournament ninth in the PIF ATP Live Race To Turin and is chasing a place at the season-ending championship.
His victory gives him an opportunity to consolidate his position ahead of Alex de Minaur, who sits 10th in the race. With the battle for qualification intensifying, every win could prove important as the season approaches its conclusion.
Arthur Fils also began his Basel campaign with a solid performance, defeating close friend Giovanni Mpetshi Perricard 7-6(5), 7-5. The Frenchman has enjoyed an impressive season, highlighted by titles at the Cincinnati Masters 1000 and Barcelona ATP 500, and will next meet Alex Michelsen.
Hubert Hurkacz, meanwhile, showed his fighting spirit by recovering from a set down to beat Zizou Bergs 3-6, 6-3, 6-4. The former Basel finalist raised his level in the deciding set, producing a crucial backhand passing shot on break point to help swing the match in his favour.
Hurkacz has won 11 of his 14 matches since the US Open, and his latest victory sets up a challenging next-round meeting with Holger Rune.
With Shelton's serving display, Jodar's push for Turin and Wawrinka's emotional farewell among the main talking points, the opening round in Basel delivered a mix of high-level tennis and memorable moments.