Kitchen had taken a 6-2 lead after four innings behind a quality start from Beatty, who allowed two earned runs on four hits over five innings, and early offense from Rivera, Max Cunning (two for four with a home run and two RBIs), Jonny Alvarado (three for three with an RBI) and Christian Rivera (three for four with an RBI).
Express, which was led by multi-hit games from Jacob Barajas, Jay Vasquez and Fidel Hernandez, cut the lead to one with three runs in the top of the sixth and tied the game on an error with Kitchen one out away from clinching the win in the top of the seventh.
But Kitchen would find redemption in the bottom of the frame, capturing its first title in three years after finishing runner-up in the last two tournaments.
"It feels great, third time's the charm," said Omar Peraza, a member of the team for the last three seasons. "It was tough, it was a real close game and [the Express] was really good too."
Express' sixth-inning rally began with a leadoff home run to deep left field by Hernandez that cut the lead to 6-3.
Christofher Rivera relieved Beatty and recorded the first out on a popup, but soon ran into trouble after allowing a three straight hits.
Alex Sanchez nestled a blooper into right field that went for a ground-rule double, Vasquez singled to right and Daniel Sahagan also singled to right to plate Sanchez and make it 6-4. Express would tack on an unearned run after a fielding error loaded the bases and Barajas drew a walk.
Hernandez ripped a ground-rule double down the left-field line to lead off the top of the seventh and tied the game when he scored from third on an error.
"They showed some character, they came back," said Express Coach Ramon Valdez, whose starter, Brandon Munoz went five innings and allowed three earned runs before yielding to Cal Moreno, who allowed one run in two innings. "They showed heart, scored some runs and made it a ball game."
Kitchen again looked to be on the verge of closing the door when Alvarado singled and Peraza and Beatty walked to load the bases with no outs in the bottom of the seventh inning.
But Moreno buckled down and induced a popout and a swinging strikeout on a full count before Christofher Rivera's long fly ball on a 1-0 pitch.
"Express played fantastic and that game could have gone either way," Kitchen Coach Larry Fitzgibbons said. "They came back and tied us, but fortunately for us, we had the last at bats and that's what I think won it for us."