Holder of the world's fastest serve at 155 miles per hour, the top-seeded Roddick almost was upstaged by the unheralded Guccione, who fired 20 aces in almost pulling off a stunning upset in San Jose.

Roddick, the top seed, managed just nine aces but ensured his place in the second-round where he will play Japanese teenager Kei Nishikori, who defeated unseeded Argentine Diego Hartfield 7-5 6-3.

The 18-year-old Nishikori is coming off a stunning win over American James Blake in Sunday's Delray Beach final to capture his first career title.

Blake, the tournament's number two, rebounded from that defeat with 6-3 6-1 victory over Sam Warburg in Tuesday's opening round.

In second-round play, fourth-seeded Czech Radek Stepanek advanced to the quarter-finals with a 7-5 7-6 (7-5) win over Bobby Reynolds, and will face the winner of Wayne Odesnik and Yen-Hsun Lu.

Eighth seed Kristof Vliegen of Belgium was sent home by American wild card Robby Ginepri 6-2 6-3. Ginepri will face the winner of the second-round match between Blake and Jesse Levine on Thursday.

Joining Ginepri in the quarter-finals will be Spaniard Guillermo Garcia-Lopez, who punched his ticket with a hard-fought 3-6 7-6 (7/3) 6-4 victory over German Benjamin Becker.

In the final match of the night, third-seeded German Tommy Haas advanced with a 6-3 4-6 6-2 win over American Robert Kendrick, and will face American John Isner.