Top seed Carlos Alcaraz withstood a charge from qualifier Luca Nardi for a 6-1, 4-6, 6-3 victory in the second round of the Qatar ExxonMobil Open in Doha on Wednesday.
The Spaniard, ranked No. 3 in the world, converted 5 of 11 break-point opportunities, to 2 of 5 for Italy's Nardi, who had five double faults.
Alcaraz won the opening set and was up 4-1 in the second when Nardi, ranked No. 85, roared back to force a third set.
Alcaraz, winner of 12 straight matches at ATP 500 events, next faces Czech Jiri Lehecka, who ousted Hungary's Fabian Marozsan 6-4, 6-2.
Second-seeded Alex de Minaur of Australia, fourth-seeded Daniil Medvedev of Russia, fifth-seeded Andrey Rublev of Russia and eighth-seeded Jack Draper of Great Britain all won matches in straight sets.
Italy's Matteo Berrettini eliminated the Netherlands' Tallon Griekspoor 7-6 (4), 6-7 (6), 6-4, and Canada's Felix Auger-Aliassime advanced by walkover of Serbia's Hamad Medjedovic, who withdrew due to a right leg injury.
Zverev extended by Shevchenko at Rio Open
Top-seeded Alexander Zverev of Germany survived a stiff second-round test in Rio de Janeiro, edging Kazakhstan's Alexander Shevchenko 7-6(1), 7-6(6).
An 18-point opening game set the tone for the tight match, which lasted 2 hours, 28 minutes despite concluding in straight sets.
Shevchenko led 6-4 in the second-set tie-breaker, but Zverev won the next four points -- two of them set points for Shevchenko -- to wrap up the match.
Fifth-seeded Sebastian Baez of Argentina, the defending champion, pulled off a 6-4, 1-6, 6-3 victory over countryman Mariano Navone.
Another Argentine, Francisco Comesana, saved a match point in the third-set tie-breaker and upset sixth-seeded Nicolas Jarry of Chile 7-6(4), 6-7 (1), 7-6 (6).
In the last match of the night, Brazil's Thiago Monteiro faced Taiwan's Chun-Hsin Tseng.