David Ferrer started his quest to win a fifth Auckland Open title with a straight-sets victory over Wu Yibing on Monday.
The veteran Spaniard was crowned champion in New Zealand for a third year in a row in 2013, having first claimed the title back in 2007.
Seventh seed Ferrer battled his way past Wu on the first day of the tournament, winning 7-6 (9-7) 6-4 as he aims to become the first man to win the event five times.
The 35-year-old was cruising in the breaker at 4-0 up but had to save two set points before edging ahead of the Chinese wildcard. He then broke twice in the second set to prevail.
Roberto Bautista Agut moved into round two by beating Michael Venus 6-2 6-1, while Denis Shapovalov and Karen Khachanov also advanced.
Qualifier Daniil Medvedev knocked Philipp Kohlschreiber out in the opening round of the Sydney International.
Russian Medvedev won 6-2 6-3 after breaking three times and saving all three break points he faced on a frustrating day for the sixth seed.
Wildcard John Millman came out on top in an all-Australian encounter with Alexei Popyrin, winning 7-6 (7-4) 6-0.
Lucky loser Ricardas Berankis accounted for Alex Bolt, while fifth seed Adrian Mannarino got the better of Evgeny Donskoy.