LONDON — Last year’s runners-up were up first on the main showcourts at Wimbledon on Tuesday, and both came through in straight sets.

Angelique Kerber, playing in the spot on Centre Court normally reserved for the defending women’s champion, beat Irina Falconi of the United States 6-4, 6-4. On No. 1 Court, Milos Raonic defeated Jan-Lennard Struff of Germany 7-6 (5), 6-4, 7-6 (4).

“A lot of memories came back when I walk on the Centre Court,” Kerber said. “Playing there again, it’s one of the best courts to play. It’s traditional, so it was really great to being back.”

Novak Djokovic and Roger Federer, who own a combined 10 titles at the All England Club, didn’t even need three sets to advance. They both reached the second round when their opponents retired from their matches in the second set.

Kerber stepped in to the opening spot on Centre Court on Day 2 in place of Serena Williams, the defending champion who is out for the rest of the season because she is pregnant.

Although Kerber became the first women seeded No. 1 in the professional era to lose in the first round of the French Open, she made it through to the second round on the grass.

“Playing first rounds in Grand Slams are always tough, especially with my first-round match that I lost in Paris,” Kerber said. “I was actually just thinking about point by point, trying to finding my rhythm during the whole match.”

Djokovic followed on Centre Court, leading 6-3, 2-0 when Martin Klizan stopped because of injury. The second-seeded Serb was leading 30-0 in the third game of the second.

“It’s really odd that Roger’s result and my result more or less was the same,” Djokovic said. “We had a little joke about it in the locker room, saying we should maybe play a practice set on the Centre Court, have the crowd stay. But they had another match.”

The victory put Djokovic alone into second place on the list of Grand Slam match wins, one ahead of Jimmy Connors, with 234. Federer, an eight-time champion who followed on Centre Court and beat Alexandr Dolgopolov, leads the list with 315.

Federer was leading 6-3, 3-0 when Dolgopolov retired.

Raonic came into Wimbledon after playing only one match on grass, a first-round loss at Queen’s. The last time he failed to win a match on grass prior to Wimbledon, in 2014, he reached the semifinals.

Last year he did even better than that, reaching the final at the All England Club and losing to Andy Murray in straight sets.

Raonic said he made good use of his time since that loss at Queen’s, however.

“Spent a lot more time training,” Raonic said. “Sort of got to the point where I was spending a lot of days practicing. I was just getting more and more eager for this tournament to start because there were a lot of days in a row.”

Juan Martin del Potro needed seven match points, but he also advanced, beating Thanasi Kokkinakis 6-3, 3-6, 7-5 (2), 6-4.