Caixa Eletronica took advantage of sizzling early fractions as he rallied from just off the pace and onto a three-length victory over Convocation in a 10-1 upset of Saturday’s Grade 3, $100,000 Westchester, the opening weekend feature at Belmont Park.

Ridden by Cornelio Velasquez, the 6-year-old son of Arromanches broke sharply, but then settled behind Christmas for Liam and 4-5 favorite Haynesfield as they rocketed through an opening quarter-mile in 22.34 and a half in 44.72. Rounding the turn, Caixa Eletronica moved up eagerly past the favorite to collar Christmas for Liam, taking command in midstretch and going on to hit the wire in 1:34.26 for the mile.

“I had a good trip,” said Velasquez, who later won Belmont’s 10th race to post four winners for the afternoon. “When I asked him, I had a lot of horse.”

Schoolyard Dreams was up to edge Haynesfield by a neck for third, with Christmas for Liam finishing fifth. Soaring Empire was scratched.

“We just had an awful set-up,” said Ramon Dominguez, aboard the beaten favorite, who was making his first start of 2011. “I was doing everything under my full power when I realized I couldn’t match strides with the horse on the outside [Christmas for Liam]. I wasn’t able to get him back as he was too fresh.”

Caixa Eletronica, making his first start for trainer Todd Pletcher and owner Mike Repole after having been claimed for $62,500 on March 9, returned $22 for a $2 win bet to his backers in the crowd of 6,766 as he earned his first career stakes win. Overall, Caixa Eletronica is 13-7-7 from 41 starts, with earnings of $321,705.

“Obviously after today Caixa looks like a great claim,” said Repole, who was on his way to Kentucky to watch his Uncle Mo and Stay Thirsty prepare for the May 7 Kentucky Derby. “It’s just another example of the great work Todd Pletcher and his assistant trainers do. I’m glad I taught him how to fill out a claim slip. It’s great winning a graded stake on the last Saturday of April. My goal is to win a graded stake on the first Saturday in May.”

Next up for Caixa Eletronica will likely be Belmont Park’s Grade 1, $500,000 Metropolitan Handicap on May 30.

“You would have to consider it,” said Jonathan Thomas, Pletcher’s assistant. “He’s a real generous horse and it seems like you can do whatever you need to do with him. Cornelio gave him a great ride.”

Velasquez, who won the riding title at the recently concluded Aqueduct spring meet, also won the second and third races with Gentle Edwin ($14.80) and J C’s Queen ($11.40) before concluding the card with a victory aboard Nutmegcuveeroyale ($12.80).