"I thought that was the best attitude I've had all year," third seed Querrey told reporters. "I was hitting second serve returns and taking cracks at them, and dominating with my forehand. It's the most aggressive I've been all year."
Querrey, who lost in the second round in Memphis last week and has never got beyond the semis at the Delray, took just 44 minutes to wrap up his match against Russell.
Xavier Malisse, a Delray winner in 2005 and 2007, cruised past Alejandro Falla 6-3 6-3 while the upset of the day belonged to Ivan Dodig, who beat fifth seed Alexandr Dolgopolov 6-3 6-3.
"First few games I was struggling," Dodig said. "Coming from indoor to first tournament outdoor, every player is struggling a bit. It was a little strange."
In the day's other match, Evgeny Donskoy beat Steve Darcis 7-6 6-3.