Emma Raducanu said her comeback victory over world number five Jessica Pegula to reach the quarter-finals of the Rothesay International in Eastbourne was one of her most "meaningful" wins as she continues to gather form for Wimbledon.

Raducanu followed up her stunning first-round win over fellow former US Open champion Sloane Stephens by digging deep to battle past American Pegula 4-6 7-6 (6) 7-5 after almost three hours in sweltering conditions.

The American, who won the Berlin WTA title last week, had looked in control early on following two breaks as she opened up a 4-1 lead. Raducanu, though, rallied to pull back level at 4-4 only to then see her serve falter again as Pegula closed out the first set.

The match appeared to be running away from Raducanu - who missed the entire grass-court season last year due to wrist and ankle surgery - after she soon trailed 2-0 in the second set having again lost her opening service game.

However, after finding her range from the back of the court and lifted by the home crowd, it was Pegula who started to wilt in the Eastbourne sun as Raducanu edged in front 4-3. Raducanu again dug deep to recover from 3-0 down in the tie-break to level the match as Pegula lashed another return into the net.

Remarkably, it was the first time in her career Raducanu had taken a set from a top-10 player and the 21-year-old built on the momentum into the deciding set as she broke twice to move 5-2 ahead.

Pegula, though, refused to go quietly and forced a break back in the next game when Raducanu lashed a return wide. After Pegula held, Raducanu had the chance to serve out for the match for a second time but the American went on to square things up again.

Raducanu came to the net to wrap up another break and move 6-5 ahead, which left her again serving for the match. Pegula then saw three break point chances missed as Raducanu rallied from 0-40 before completing a remarkable fightback.

"I am pretty drained right now but I just want to say thanks to everyone again for getting me through some really difficult moments in that match," Raducanu said in her courtside interview.

"It is incredibly difficult when you are playing someone so in form like Jessica. She came off the back of a great run in Berlin and no doubt she is feeling confident on the grass.

"I am really pleased with how I managed to navigate some really tough situations and I didn't think I would be able to get myself out of it, so I would say this match is one of the more meaningful ones to me. I have been going through some stuff, so to come through has been really nice."

Earlier, British number one Katie Boulter had also moved into the quarter-finals by beating Jelena Ostapenko in straight sets.

The British number one held off a second-set fightback from Ostapenko to defeat the 2017 French Open champion 6-4 7-5.

It was another step forward for 27-year-old, who won her first WTA Tour title in Nottingham last year and then beat Raducanu on her way to defending that crown this summer.

"It's definitely taken a lot of pressure off me," Boulter said. "This season is a slightly different situation for me. Today was a match I had nothing to lose, just swinging and having fun."

Boulter goes on to meet third seeded Italian Jasmine Paolini, who went through to the quarter-finals after Elise Mertens retired in the first set of their match.

Britain will have three women into the last eight of the tournament for the first time in more than 40 years after Harriet Dart beat Sofia Kenin 6-3 6-7 (3) 6-0.

"It is really good healthy competition," Raducanu said. "We all see each other progressing into the next round and just want to join them - no-one wants to be left behind.

"That is the way it should be, pushing each other, and that is definitely the case now in the men and women. We are all doing really well, especially on the grass. We all come alive on this surface, so I am very pleased and it is a testament to how we have been training and putting training in. Contrary to some beliefs about us I think we are all doing a pretty good job."