Up next for Novak Djokovic will be Nick Kyrgios in the quarter-finals; second seed Nadal will take on Yoshihito Nishioka, while defending champion Dominic Thiem takes on American Sam Querrey! Marin Cilic and Steve Johnson face each other in the quarters too - a packed field and how!
Break point and match point for Djokovic here. If anyone needs to learn how to keep a cool head, Djokovic should be their teacher. Del Potro's trusty forehand is a bit all over the place at the moment...
Almost 1 a.m. in Acapulco and neither player seems to show the signs of winding down! But here, it's Djokovic who shifts the momentum firmly in his favour as he holds to consolidate a break. He leads 5-4, and Del Potro will serve to stay in the match.
On that occasion, though, Djokovic rushes the net - and finishes it off with a lovely passing shot. We're dead even in the decider right now, and whoever wins will need to catch up on their sleep - and quickly!