An all-American battle on centre court saw Gauff dismantle Pegula, 6-3, 6-3 to advance to the semi-final. In a match that saw doubles partners turn rivals, it was the 19-year-old who found the early breakthrough to take the opening set, but Pegula soon found her way back into the contest in the second.
With aggressive ball striking from both players, world No.3 Pegula edged an early break before a momentum shift saw Gauff win six consecutive games to wrap up the match win in style. She will now go on to face another compatriot in Keys, who recorded a comprehensive win over Petra Martic 6-4, 6-1 to reach the final four.
In a highly-anticipated encounter, Daria Kasatkina moved through to the semis after France's Caroline Garcia was forced to retire at 6-2, 2-1 due to a right shoulter injury.
After a rain delay caused a late start on Thursday at the Rothesay International, Francisco Cerundolo soon got centre court proceedings underway with a 6-2, 6-3 victory over Zhizen Zhang
Eager to make a fast start to reach a first semi-final on the grass, Cerundolo clinched an early break on Zhang’s serve, before securing a second to seal the opening set.
Despite going down an early break, the Argentine soon turned it around – as he got the scoreboard back on level terms before finding a break of his own to eventually secure the match win.
He's now set to face Mackenzie Mcdonald the final four, after the American knocked out Mikael Ymer in the quarter-final.
An all-American show in the men's draw saw second seed Tommy Paul get the better of J.J. Wolf in a 6-4, 4-6, 6-3.
Joe Salisbury and Rajeev Ram's title hopes came to an end at the hands of Nikola Mektic and Mate Pavic, after losing out 6-2, 6-2.
The Croatian duo will now face reigning cinch Championships winners Austin Krajicek and Ivan Dodig in a bid for the trophy, after they knocked out Australian pair Matthew Ebden and John-Patrick Smith.
Day one of the wheelchair action, saw Greg Slade and Lucy Shuker make winning starts to their campaigns at Devonshire Park while Abbie Breakwell and Ruby Bishop fell short.
In the quad singles draw, Slade’s competitive grass court match debut saw the British No.2 win 11 games in a row to beat Gary Cox 6-3, 6-0.
Elsewhere, Shuker beat British No.4 Bishop 6-1 6-0 in 45 minutes as she reached the semi-finals in Eastbourne for the first time, where top seed Diede de Groot awaits. However, it wasn't meant to be for British No.3 Breakwell, who lost out to China’s world No.5 and 2022 semi-finalist Zhenzhen Zhu 6-2, 6-2.
1. EASTBOURNE, ENGLAND - JUNE 29: Coco Gauff of the United States plays a forehand during her singles match against Jessica Pegula of the United States at the Rothesay International Eastbourne at Devonshire Park on June 29, 2023 in Eastbourne, England. (Photo by Justin Setterfield/Getty Images)
EASTBOURNE, ENGLAND - JUNE 29: Coco Gauff of the United States plays a forehand during her singles match against Jessica Pegula of the United States at the Rothesay International Eastbourne at Devonshire Park on June 29, 2023 in Eastbourne, England. (Photo by Justin Setterfield/Getty Images):Action from Thursday's play at the Rothesay tennis international at Devonshire Park, Eastbourne Photo: Justin Setterfield:Getty Images
2. US player Jeffrey John Wolf returns to US player Tommy Paul during their men's singles quarter-final tennis match at the Rothesay Eastbourne International tennis tournament in Eastbourne, southern England, on June 29, 2023. (Photo by Glyn KIRK / AFP) (Photo by GLYN KIRK/AFP via Getty Images)
US player Jeffrey John Wolf returns to US player Tommy Paul during their men's singles quarter-final tennis match at the Rothesay Eastbourne International tennis tournament in Eastbourne, southern England, on June 29, 2023. (Photo by Glyn KIRK / AFP) (Photo by GLYN KIRK/AFP via Getty Images):Action from Thursday's play at the Rothesay tennis international at Devonshire Park, Eastbourne Photo: GLYN KIRK:Getty Images
3. US player Tommy Paul returns to US player Jeffrey John Wolf during their men's singles quarter-final tennis match at the Rothesay Eastbourne International tennis tournament in Eastbourne, southern England, on June 29, 2023. (Photo by Glyn KIRK / AFP) (Photo by GLYN KIRK/AFP via Getty Images)
US player Tommy Paul returns to US player Jeffrey John Wolf during their men's singles quarter-final tennis match at the Rothesay Eastbourne International tennis tournament in Eastbourne, southern England, on June 29, 2023. (Photo by Glyn KIRK / AFP) (Photo by GLYN KIRK/AFP via Getty Images):Action from Thursday's play at the Rothesay tennis international at Devonshire Park, Eastbourne Photo: GLYN KIRK:Getty Images
4. US player Tommy Paul returns to US player Jeffrey John Wolf during their men's singles quarter-final tennis match at the Rothesay Eastbourne International tennis tournament in Eastbourne, southern England, on June 29, 2023. (Photo by Glyn KIRK / AFP) (Photo by GLYN KIRK/AFP via Getty Images)
US player Tommy Paul returns to US player Jeffrey John Wolf during their men's singles quarter-final tennis match at the Rothesay Eastbourne International tennis tournament in Eastbourne, southern England, on June 29, 2023. (Photo by Glyn KIRK / AFP) (Photo by GLYN KIRK/AFP via Getty Images):Action from Thursday's play at the Rothesay tennis international at Devonshire Park, Eastbourne Photo: GLYN KIRK:Getty Images