Serena Williams and sister Venus won at the BNP Paribas Open at Indian Wells to set up a third-round clash in the desert tournament.

Serena got by No29 seed Kiki Bertens of the Netherlands 7-6 (5), 7-5 in the second round on Saturday in her return from a 14-month absence after giving birth to her first child. Venus preceded her younger sister on the stadium court and beat Sorana Cirstea of Romania 6-3, 6-4.

The sisters will resume their longtime rivalry on Monday. Serena leads Venus 17-11 all-time and has won eight of their last nine meetings, most recently the Australian Open final last year.

Wild card Danielle Collins defeated US Open finalist Madison Keys 6-3, 7-6 (1) to continue a string of upsets.

Keys hasn’t made it past the fourth round at Indian Wells in eight tries. The No15 seed was mistake-prone throughout the second-round match, committing five unforced errors in the tiebreaker.

Collins, ranked 116th and making her first appearance in the main draw, is just starting her second year on the WTA Tour.

She joined American upset winners Sachia Vickery, who beat No3 seed Garbine Muguruza; 16-year-old wild card Amanda Anisimova, who beat No23 seed Anastasia Pavlyuchenkova; and wild-card teenager Caroline Dolehide, a three-set winner over No. 30 Dominika Cibulkova on Friday.

In other matches Saturday, defending champion Elena Vesnina eliminated American CiCi Bellis 2-6, 6-1, 6-1; No4 seed Elina Svitolina beat Mona Barthel 6-4, 6-3; No12 Julia Goerges defeated Natalia Vikhlyantseva 6-4, 6-1; No27 Carla Suarez Navarro beat Su-Wei Hsieh 6-4, 2-6, 6-3; and No26 Daria Gavrilova dismissed Yanina Wickmayer 7-6 (3), 6-2.

Two seeded players lost: No18 Magdalena Rybarikova and No28 Anett Kontaveit.

On the men’s side, No3 Gregor Dimitrov was upset by Fernando Verdasco 7-6 (4), 4-6, 6-3 and No16 Fabio Fognini went down against Jeremy Chardy 4-6, 7-6 (2), 6-4.

Fifth-seeded Dominic Thiem fired 10 aces to beat Stefanos Tsitsipas of Greece 6-2, 3-6, 6-3; No7 Kevin Anderson defeated Evgeny Donskoy 7-5, 6-4; and No12 Tomas Berdych rolled past German Maximilian Marterer 6-1, 6-4 in just over an hour.

No30 Pablo Cuevas beat Denis Shapovalov 7-6 (4), 6-3.