Memphis, TN –  American favorite Sam Querrey was an easy winner, while defending champion Jurgen Melzer and John Isner suffered opening-round defeats Tuesday at the $1.212 million U.S. National Indoor Tennis Championships.

The fourth-seeded former champion Querrey conquered Colombian Alejandro Falla 6-3, 6-3 on Day 2. The 6-foot-6 Querrey captured this event three years ago.

Meanwhile the veteran Austrian left-hander Melzer succumbed to Dutchman Igor Sijsling 6-4, 7-6 (7-3) at The Racquet Club of Memphis. Sijsling is rewarded with a second-round match against top-seeded Marin Cilic of Croatia.

Melzer beat Canadian slugger Milos Raonic in last year's finale here.

Denis Istomin took down Isner, the No. 3 seed, by a 6-4, 6-3 margin. Isner was the 2010 runner-up here to Querrey.

Fifth-seeded Kei Nishikori of Japan beat Illya Marchenko of Ukraine by a 6-4, 7-5 margin.

Wild card and veteran American crowd favorite James Blake landed in the win column by beating capable German Florian Mayer 4-6, 6-3, 6-2. Blake was a Memphis runner-up 11 years ago.

Also on Tuesday, American journeyman and lucky loser Michael Russell topped Russian qualifier Alex Bogomolov Jr. 6-2, 6-4. Feliciano Lopez defeated Benjamin Becker 4-6, 6-3, 6-4.

The 2013 Memphis champ will claim $291,800.