Great Britain's Jack Draper made it through to the second round of the Mexican Open with victory over Tommy Paul, but Dan Evans fell to defeat against Ben Shelton.
Draper earned the latest scalp in his rivalry with the USA's Paul, whom he thrashed 6-0 6-4 in Acapulco, but Evans could not build on a lightning quick start against Shelton in a 6-2 5-7 6-7[5] defeat.
Monday's first-round showdown marked the third meeting between Draper and Paul already in 2024; the Briton bested the world number 14 in the Adelaide International quarter-finals before Paul dumped him out of the Australian Open in the second round.
Draper had only taken to the court once on the ATP Tour since his Grand Slam elimination - losing to Thanasi Kokkinakis in the first round of last week's Los Cabos Open - and the 22-year-old immediately came under pressure against his more experienced foe.
However, after beating away three break points for Paul in the opening game of the match, a vengeful Draper went on the warpath and inflicted a bagel on his opponent in the opening set, while only dropping one point in his next two service games.
Paul managed to hold his own in the second set, significantly improving his first-serve win percentage, but while serving to stay in the match, the American shanked a forehand wide to send Draper through.
Paul's final mishit shot represented his 12th unforced error of the day, while an on-song Draper struck 13 winners to progress to the last 16, where Japanese lucky loser Yoshihito Nishioka awaits.
Evans could not join his countryman in the second round, though, as the 33-year-old fell short in his first-ever top-level encounter with a man 12 years his junior in Shelton.
Evans benefitted from early errors from the former US Open semi-finalist, winning four games on the spin from 2-2 in the first set, which he concluded in style with an ace for a love hold.
Only two service points were dropped between both men in the first five games of the second set, but a catastrophic 12th game for Evans saw the Briton broken to love as Shelton engineered a deciding set.
The rejuvenated American racked up the winners count in the third set and raced into a 40-0 lead while returning for the match in the 10th game, but Evans was not ready to concede defeat, fighting back to hold before a break to love in the 11th.
However, the world number 41 could not hold his nerve while serving for the match as Shelton bit back to force a tie-breaker, and on his first match point, a well-executed serve and volley from the American punched his ticket to round two, where Italy's Matteo Arnaldi awaits following his shock three-set win over Taylor Fritz. body check tags ::