Top seed Iga Swiatek will be hard top stop in her title defence at the Indian Wells Open after a straight-sets thrashing over Emma Raducanu in Tuesday's last 16.

The Polish world number one eased to victory 6-3 6-1 in one hour and 25 minutes over the 2021 US Open champion, who has enjoyed an improved run this week in California.

Swiatek offered few weaknesses in a strong disciplined display, converting four of 10 break points, including three in a one-way second set.

The three-time major winner won 88 per cent on her first serve while she was impressive on return and able to win the longer rallies. Swiatek hit 22-9 winners while Raducanu made 22-14 unforced errors.

Swiatek will take on Romania's Sorana Cirstea in the quarter-finals, after she upset fifth seed Caroline Garcia 6-4 4-6 7-5 in two hours and 24 minutes.

Reigning Wimbledon champion Elena Rybakina also progressed in that part of the draw, setting up a last-eight clash with unseeded Czech Karolina Muchova.

Rybakina won 6-3 6-0 over qualifier Varvara Gracheva in a similarly strong performance, needing only one hour and 21 minutes. Muchova beat compatriot Marketa Vondrousova 6-4 6-7 (2-7) 6-4 in two hours and 37 minutes.

Third seed Jessica Pegula was the major casualty of the day's play, going down 6-2 3-6 7-6 (13-11) to 16th seed Petra Kvitova in a dramatic two-hour-and-16-minutes clash.

Pegula had opened up a 5-3 third-set lead and squandered a match point on serve, before two-time Wimbledon winner Kvitova squared it up at 5-5. Kvitova, however, was broken immediately to offer Pegula another chance to serve out the match again, which she was unable to take.

The American generated another three match points in the tie-break but could not convert before the Czech eventually prevailed on her own fourth match point, with the deciding set lasting one hour and 12 minutes.

Kvitova will face seventh seed Maria Sakkari in the quarters after she triumphed in a lengthy clash 6-4 5-7 6-3 over Karolina Pliskova, lasting two hours and 43 minutes.

Second seed Aryna Sabalenka also needed three sets to beat Barbora Krejcikova 6-3 2-6 6-4 in two hours and four minutes. Krejcikova had been responsible for Sabalenka's lone loss this season, in a 15-1 year.

Sabalenka, who won this year's Australian Open, will face sixth seed Coco Gauff who defeated Rebecca Peterson 6-3 1-6 6-4. Gauff won the last four games for victory, having trailed 4-2 in the deciding set.