Top seed Novak Djokovic overcame a dogged challenge from 81st-ranked Korean Kwon Soon-woo and his own grasscourt rustiness to reach the Wimbledon second round.
The defending champion registered a 6-4 3-6 6-3 6-4 victory on Monday.
Djokovic, who is bidding for his fourth Wimbledon title in a row and his seventh overall, looked out-of-sorts at times against Kwon, who brought a lively mixture of tennis, from booming forehands to delicate drop-shots, onto Centre Court.
Djokovic had not played a grasscourt warm-up tournament and he admitted that did not help his game against a tough opponent, 11 years his junior.
Elsewhere, Norwegian third seed Casper Ruud registered his maiden Wimbledon victory in his third main-draw appearance when he saw off experienced Spaniard Albert Ramos-Vinolas 7-6(1) 7-6(9) 6-2 in the first round.
French Open runner-up Ruud failed to get past the opening hurdle in 2019 and 2021 and arrived at this year's grasscourt Grand Slam following a first-round loss at Queen's to world number 180 Ryan Peniston.
In the women's competition, Emma Raducanu marked her Centre Court debut with a 6-4 6-4 win over 10th seed Alison Van Uytvanck of Belgium.
Britain's US Open champion was playing her first match since retiring from a match due to a rib injury three weeks ago.
Third seed Ons Jabeur powered past Mirjam Bjorklund 6-1 6-3.
The Tunisian, a quarter-finalist last year, showed no signs of being hampered by the knee injury that forced her out of the Eastbourne tune-up event.
Switzerland blank Algeria, reach round of 16 for 4th straight World Cup
Portugal survive late drama to beat Croatia
Anisimova and Fritz through as Americans sparkle at Wimbledon
Spain outclass Austria 3-0 to ease into World Cup last 16
Swiatek, Zverev power into Wimbledon round three
