No.1 seed Aryna Sabalenka, Iga Swiatek, and Coco Gauff all claimed first-round victories on a jam-packed Tuesday afternoon into evening at the Viking International in Eastbourne.

Following a complete washout on Monday, forcing all 16 first-round matches to take place on Tuesday, Sabalenka had one of the relatively easier finishes, as she moved past American qualifier Bernarda Pera, 6-3, 6-4, in just over an hour of play.

World No.4 Sabalenka reached the Eastbourne final in 2018, her career-best showing at a WTA grass-court event. The Belarusian took her first step towards matching that feat as she improved to 2-1 against left-handed Pera, ranked 71st in the world.

Pera stormed to an early lead in their match, winning seven of the first eight points en route to a 2-0 lead. But Sabalenka pulled back level when Pera double faulted on the top seed's fourth break point in the 2-1 game.

That was part of a run of five straight games where Sabalenka opened up a 5-2 advantage, and she closed out the set by punctuating a love service hold with an unreturnable serve.

Sabalenka was never broken in the second set, and she took the lead for good by breaking for 4-3 with a powerful, error-forcing backhand. Another love service hold, ending with an ace, wrapped up the match, and Sabalenka booked her spot in the second round.

Last year's Roland Garros champion Iga Swiatek had a much more difficult time as she needed two hours and 42 minutes to quell the challenge by British hope Heather Watson, 6-3, 6-7(4), 7-5 on Centre Court.

No.4 seed Swiatek claimed her first-ever WTA main-draw win on grass with her victory over 65th-ranked Watson, as the Pole had only played two matches at this level on the surface in 2019, and lost them both.

Swiatek very nearly went 0-for-3 on the surface as she was down a double-break in the final set before storming back to win six of the last seven games and keep her hopes for an Eastbourne title alive.

"I think I was just fighting, and even though grass is not the surface I understand completely, I kept believing that I can do it anyway," Swiatek said, in her post-match press conference. "I have, you know, some weapons that I can use. When I became more loosened up in the third set, it helped me a lot. I think it's the key when you're playing on grass."

Swiatek outlasts Watson for 1st main-draw win on grass: Eastbourne Highlights

2021 Eastbourne

World No.9 Swiatek needed just a single break to take the first set, then slid ahead by a break in the second set as well at 4-2. But untimely errors from Swiatek ceded the break right back to Watson, and the British hope took full advantage as she ramped up her aggression to send the second set into a tiebreak.

In the breaker, Watson leapt out to a 3-0 lead and eased home from there, leveling the match. Watson kept up the momentum in the decider, slamming an incredible backhand return winner to earn her second break of the set and grasp a commanding 4-1 lead.

Watson had two game points for a 5-1 lead, but Swiatek regrouped, breaking for 4-2 with a forehand crosscourt winner, and the tables suddenly turned.

A dropshot winner on break point pulled Swiatek back level at 4-4, and two games later, the Polish player saved a break point with a forehand winner, eventually edging ahead 6-5. There, Swiatek got the decisive break as she completed her comeback victory.

"The whole match was pretty crazy," Swiatek said. "You could see that I have a love/hate relationship with grass. I'm pretty happy that I came back in the third set."

Gauff also had a comeback victory with an even more unexpected scoreline, as the American teenager defeated No.7 seed Elise Mertens of Belgium, 0-6, 7-6(4), 7-5.

World No.23 Gauff stormed back from being bageled in the first set to clinch victory after two hours and 13 minutes of play, in her first match since she reached her first Grand Slam quarterfinal at Roland Garros, where she fell to eventual champion Barbora Krejcikova.

Gauff is playing just her second tour-level main draw on grass -- her only previous tour-level event on the surface was her breakout performance at 2019 Wimbledon, where she famously reached the round of 16 as a 15-year-old qualifier.

Against Mertens, Gauff used her signature grit to pull herself out of multiple deficits, as she was down a break three times in the second set. Mertens served for the match at 5-4 and 6-5 in the second set, and each time, Gauff prevailed to break right back.

In a crucial second-set tiebreak, all-court rallies came fast and furious, but it was ultimately the American who claimed the breaker, and the set, using a deep forehand to force an error from Mertens.

Mertens led by a break at 4-2 in the third set as well, but Gauff again broke back immediately, and Gauff then saved five break points during a hold for 4-4. Gauff was rewarded for her determination as she eked ahead 6-5, after a service break at love. The teenager swept to triple match point in the next game, and finished off her comeback with a forehand winner.

Belinda Bencic during her first-round match in Eastbourne.

Photo by WTA/Jimmie48

No.6 seed Belinda Bencic joined those winners in the second round, charging past Petra Martic, 6-1, 6-3, in just 52 minutes. Bencic converted all four of her break points and saved the only one she faced in the match.

It was the second straight week Bencic beat Martic, as she also picked up a win over the Croat during her run to last week's final in Berlin. Bencic thus keeps her hope alive for a second Eastbourne crown -- this is the site of the Swiss star's maiden WTA singles title, which came in 2015.