With only two of the four scheduled singles matches completed, rain saw the day's play suspended.

The blockbuster clash between top seed Cilic and Frenchman Monfils was stopped in a second-set tie-break.

Monfils took the first set 6-3 and the duo were locked at 7-7 in the tie-break when play was suspended for the day.

Cilic had recovered from a break down in the second set and squandered two set points, while also saving a match point.

Ramos-Vinolas exited in one of two completed matches, losing to Nicolas Jarry 7-5 6-3.

The day's other match saw sixth seed Diego Schwartzman cruise past fellow Argentinian Federico Delbonis 6-2 6-3.