Lehecka also saved nine of 11 break points and collected 53 winners to pull off the day's only upset. He trailed 4-2 in the third set but proceeded to win the final four games to punch his ticket to the quarter-finals, where he will face seventh seed Alexander Bublik of Kazakhstan.
Bublik was a 7-6(8), 7-6(2) winner over the Netherlands' Tallon Griekspoor on Wednesday.
No. 1 seed Daniil Medvedev of Russia and countryman Andrey Rublev, the No. 2 seed, also made it through the second round. Medvedev fought back to oust Italian Lorenzo Sonego 3-6, 6-3, 6-3, while Rublev swept French qualifier Arthur Cazaux 6-4, 6-4.
In other action, No. 3 seed Hubert Hurkacz of Poland, fifth-seeded Frenchman Ugo Humbert, eight-seeded Spaniard Alejandro Davidovich Fokina and the United States' Sebastian Korda all prevailed.
Movistar Chile Open
Spain's Pedro Martinez outlasted sixth seed Facundo Diaz Acosta of Argentina for a 7-6(4), 6-7(5), 6-1 win in second-round action in Santiago, Chile.
After the first two sets were competitive, Martinez ran away with the third to cap a marathon match that lasted 3 hours, 8 minutes. He will next face third-seeded Frenchman Arthur Fils, who defeated Brazil's Thiago Seyboth Wild 6-3, 6-3 on Wednesday.
No. 1 seed Nicolas Jarry of Chile cruised past Argentina's Federico Coria 7-6(4), 6-2, and French qualifier Corentin Moutet toppled Argentine Thiago Agustin Tirante 6-3, 6-7(5), 6-2.
Abierto Mexicano Telcel
Germany's Dominik Koepfer won 12 of 14 points on his serve in the third set and emerged with a 6-4, 5-7, 6-1 win over eighth-seeded Frances Tiafoe of the United States in second-round action at Acapulco, Mexico.
The top three seeds in action all earned straight-set victories. No. 2 Holger Rune of Denmark ousted the United States' Aleksandar Kovacevic 7-6(5), 6-2. No. 3 Alex de Minaur of Australia trounced Austria's Sebastian Ofner 6-1, 6-3, and No. 5 Stefanos Tsitsipas of Greece beat Italian qualifier Flavio Cobolli 6-3, 7-6(6).
In other action, Great Britain's Jack Draper handled Japan's Yoshihito Nishioka 6-3, 6-0; Serbia's Miomir Kecmanovic downed Germany's Daniel Altmaier 6-4, 6-4; and the United States' Ben Shelton defeated Italy's Matteo Arnaldi 7-6(1), 3-6, 6-3.
In the final match of the night, sixth-seeded Casper Ruud of Norway got the only two service breaks in the last game of each set en route to a 6-4, 7-5 win over Serbia's Dusan Lajovic.
