Big serving American Sam Querrey was bounced out of the Atlanta Open in the second round on Wednesday by Israel's Dudi Sela 6-2 6-4.
Despite notching eight aces to none and winning 86 percent of points on his first serve, ninth seed Querrey won just six of 26 second serve points to be ousted by the world No. 94.
It wasn't the only shock of the second round with sixth seed Denis Istomin of Uzbekistan taken out by Slovakia's world number 91 Lukas Lacko 5-7 6-1 6-4.
Lacko saved eight of 12 break points to catapult him towards victory as Istomin could only save one of seven.
In other second round matches fourth seed Canadian Vasek Pospisil beat qualifier Illya Marchenko of Ukraine 7-5 6-3 to set up a date with Sela, while 21-year-old American Jack Sock took out New Zealand's Michael Venus 6-4 6-2 to advance to a third round encounter with Lacko.
"Obviously the summer is going pretty well so far," Sock told reporters as he primes himself ahead of the US Open.
"I won some matches at the French (Open), Wimbledon was a great showing for me, Newport winning three matches and two matches here so far, so confidence is probably the highest it has ever been."
Earlier Taiwan's Lu Yen-Hsun, the seventh seed, completed the first round with a 6-4 6-4 win over American Alex Kuznetsov.