SAN JOSE — Lyndsey Dworkin woke up Saturday morning, climbed out of bed and asked her mom a question.

“Did that all really happen last night?” she wondered. “Otherwise, I just had the craziest dream.”

It was real, her mom assured her. Every magical moment.

Brandon Belt really did tell the 12-year-old cancer survivor that he would hit a home run for her at the San Jose Giants game. And Belt really did deliver in the first inning, blasting a towering shot over the right-field fence at Municipal Stadium.

The autographed home run ball sitting in the Dworkin home in Mountain View now serves as proof. It says: “To Lyndsey, My Good luck charm. — Brandon Belt.”

Belt made his promise just before game time, after watching Lyndsey throw out the ceremonial first pitch. The girl had chosen to wear a Belt T-shirt for the occasion, so as she trotted off the mound, Belt raced out of the dugout to say hello.

Belt, on a rehab assignment from a broken thumb, felt an instant kinship with the girl on the mend. Lyndsey has undergone 31 bouts of radiation and nine rounds of chemotherapy. At the end of the conversation, Belt told her: “I’m going to hit a home run for you.”

Kristine Dworkin, the girl’s mom, was among those who was listening.

“I thought, ‘What a sweet thing to say. He seems like a nice guy,’ ” Kristine said.

“I thought, ‘C’mon, Brandon. A home run? Maybe promise a single,’ ” said Juliana Paoli, the San Jose Giants chief marketing officer.

And Lyndsey’s reaction?

“I kind of forgot about it,” she said with a laugh Saturday. She was thrilled to have met Belt, but it wasn’t until Paoli came bearing the souvenir ball retrieved from the parking lot that the kid remembered the home run promise. “That’s when I said, ‘Oh, yeah. He did say that.’ “

Belt blasted his home run with two outs and nobody on against Braden Shipley, kick-starting an 8-3 victory over Visalia. It was his first long ball of the comeback attempt from the injury he sustained May 9 when he was hit by a pitch at Dodger Stadium.

Belt now has extended an invitation to the Dworkin family to come to AT&T Park whenever he gets activated from the disabled list. The first baseman, who was sent to Triple-A Fresno on Saturday to continue his rehab, is already making arrangements to make sure they can be on the field during batting practice at AT&T.

The whole crazy dream began a year ago when Lyndsey attended a San Jose Giants game with her mom on Breast Cancer Awareness Night. Lyndsey — usually more jock than princess — surprised her family by fixating on the pink jerseys up for a charity auction that night.

After hearing the girl’s story, Paoli promptly removed one from the auction for the team to later present to Lyndsey. A student at Blach Intermediate School in Los Altos, Lyndsey had been diagnosed with medullablastoma, a brain tumor. Originally, doctors thought the cause of her pain was minor and suggested Advil and lots of water.

But Kristine Dworkin kept watching the way her star soccer player was suddenly struggling with basic coordination, just to keep her balance, and demanded that doctors do a more thorough exam. That’s when they found the tumor. “She has a mother who doesn’t take no for an answer,” the mother said.

With help from the Lucile Packard Children’s Hospital at Stanford, Lyndsey appears headed for a full recovery. She recently walked a 5K in honor of a fellow patient, Taylon Davis, who died at 12 of a rare form of bone cancer.

Lyndsey’s next step was taking the trip to the mound. Before she did, the San Jose Giants gave her the run of the team store. (Asked about the best part of her Friday night, Lyndsey picked the shopping spree.)

Lyndsey, at 1﻿1/2 years since the original diagnosis, put on her brand new Belt shirt and delivered her best fastball.

“A little bit to the right,” she said. “But it was better than I thought it would be.”

Everything else went just like a dream.