Haas, ranked 10th in the world and the 2004 champion here, converted five of 12 break points to defeat the 19-year-old Californian for the third straight time this season.
Both players had a rough time serving, Haas connecting on 49 percent of his first serves while Querrey, who suffered his first opening round loss of the year, managed just 51 percent.
German Haas, seeking his 12th career title, will face France's Nicolas Devilder in the second round of the $416,000 tournament.
In other first round matches, Argentine Diego Hartfield stopped Frenchman Sebastien Grosjean 6-4 6-4, while American qualifier Alex Kuznetsov knocked out Lars Burgsmuller of Germany 7-5 7-5.
Austrian Jurgen Melzer, a finalist a year ago, defeated Romanian Victor Hanescu 6-4 6-2 in second-round action, while Spain's Albert Montanes needed three sets to squeeze by Dusan Vemic of Serbia 6-4 4-6 6-4.
