Evergreen bullet-serving Croat Ivo Karlovic fought off two match points to dispatch Tommy Robredo at the Barcelona Open Banc Sabadell.
The 39-year-old blasted 29 aces en route to a 6-7 (5/7) 7-6 (8/6) 6-4 victory to progress to the second round in his first appearance in Barcelona in 10 years.
Karlovic became the oldest player to make the semi-finals of an ATP tour event when reaching the last four in Houston's US Men's Clay Court Championships just two weeks ago.
The 6ft 11in powermonger has again extended that fine form, and will now face eighth seed Roberto Bautista Agut.
Stefanos Tsitsipas toppled Corentin Moutet 6-4 6-1, with the 19-year-old adding to his already-impressive breakthrough campaign by rising to 63 in the world rankings.
The Greek teen star will now face seventh seed Diego Schwartzman.
Benoit Paire swept past Chile's Nicolas Jarry 7-6 (7/4) 6-7 (3/7) 6-4 to book a meeting with fifth seed Pablo Carreno Busta, with wildcard Marcel Granollers strolling past Mikhail Kukushkin 6-2 6-2.
Aljaz Bedene subdued Marius Copil 6-7 (3/7) 7-5 6-3 to progress at Budapest's Gazprom Hungarian Open.
Slovenia's world number 57 will now face either Matteo Berrettini or Attila Balazs.
Italy's Marco Cecchinato saw off Mirza Basic 6-3 6-4 and will now take on second seed Damir Dzumhur for a place in the third round.
Australia's John Millman overcame Moldova's Radu Albot 6-4 7-5 to set up a second-round clash with top seed Lucas Pouille.
