USA’s Jared Donaldson took the No. 4 seed Grigor Dimitrov into the fifth set. He was exhausted and his leg cramps limited his ability to serve,  so Donaldson broke out some some trickery to catch Dimitrov off guard.  

Here’s the rarely seen and never used Underhand serve below:

Some fans criticized the move for its lack of etiquette, but the tactic is a perfectly legal one within the rules, and helped the struggling Donaldson. You do what you have to do. Not sure when we’ll see that again, so let’s just appreciate it. 

Dimitrov fought his way to a 6-7, 6-4, 4-6, 6-4, 10-8 victory to advance into the third round. Almost worked Jared.