It continued Gauff’s shaky start to the clay-court season following on from a second-round exit in Stuttgart last week. The 19-year-old American reached the French Open final last year.
Badosa, on the comeback trail after slumping from number two in the world last year to her current ranking of 42, improved her career head-to-head record against Gauff to 3-1
The 25-year-old, who has yet to win a title on the WTA Tour, now awaits the winner of the late-night match between Maria Sakkari and wildcard Rebeka Masarova.
Teenager Andreeva continues incredible run
Elsewhere, Russian teenager Mirra Andreeva’s incredible run in Madrid continued with a straight-set victory over Poland’s Magda Linette to reach the last 16.Andreeva, given a wildcard for the event, celebrated her 16th birthday on Saturday with a confident 6-3 6-3 win over the world number 19.
Andreeva’s triumph over 2023 Australian Open semi-finalist Linette comes after she beat Brazil’s world number 14 Beatriz Haddad Maia in round two, just 24 hours after overcoming 2021 US Open finalist Leylah Fernandez.
The world number 194 will now face second seed Aryna Sabalenka in the next round.
The Belarusian beat Columbia’s Camila Osorio 6-4 7-5 to advance earlier on Saturday.