Rafael Nadal was two points away from levelling his quarterfinal against an inspired Diego Schwartzman when rain halted play at the French Open on Wednesday.

Schwartzman ended the out-of-sorts world number one's sequence of 37 consecutive sets won in the clay-court major to raise hopes of pulling off an almighty upset on Court Philippe Chatrier.

The 10-time Roland Garros champion was a break down at 3-2 in the second when the weather halted Schwartzman's momentum and Nadal returned from the interval with a spring in his step to take a 5-3 lead.

Nadal - who had his left wrist taped after losing his first set in his favourite tournament since 2015 - was 30-15 up and serving to make it a set apiece when the heavens opened again and no further play was possible.

A fearless Schwartzman took inspiration from David and Goliath as he fought back from two sets down to beat Kevin Anderson in the fourth round and slayed Nadal - who struggled on serve and returned poorly - in the first set.

The top seed saved four break points in the opening game but was a break down at 2-1 when the world number 12 thrashed away a forehand winner.

Nadal was back on serve immediately when the exuberant underdog put too much on a groundstroke, but Schwartzman regained the advantage with a simple volley to lead 4-3 after toying with the Spaniard.

Schwartzman failed to consolidate the break again, but was undeterred as a ferocious forehand winner put him 5-4 up, and another fizzed forehand winner ended Nadal's long run of sets won in a row in Paris after a stoppage when a spectator collapsed.

The defending champion had his arm taped up at the end of the first set and the Schwartzman forehand left him in even more pain, the 25-year-old holding a 3-2 advantage following three successive breaks when rain halted play.

Nadal came out firing following the resumption, winning three straight games in quick time before play was halted again.

Marin Cilic and Juan Martin del Potro were locked at 5-5 in a first-set tie-break when their quarterfinal was suspended.