Surprise (22-9), which clinched the West Division title and a spot in the Championship Game on Wednesday, must win four of its final five games to achieve the highest winning percentage in AFL history. The Mesa Solar Sox (.705) went 31-13 in 1999.
The Saguaros also are hoping to end a 16-year title drought that's the longest in league history.
"I feel like every day we have a chance to win with the hitters and pitchers we have," Olt said. "That's a good a thing to have. There's not much talk about [the record], but it has been brought up. We're just going out there and playing one game at a time."
Olt led off the second with a homer and Marlins prospect Kevin Mattison drew a bases-loaded walk to give Surprise an early lead against Brewers left-hander Jed Bradley.
"He threw me two good changeups, but I got ahead in the count," Olt said. "He has a really good two-seamer that comes out of the same arm angle as his changeup, and that makes it difficult. I guess I was waiting on it."
The Javelinas scored six runs over the second and third innings, aided by solo homers by Ryan Jackson (Cardinals) and Nick Franklin, the Mariners' No. 3 prospect.
With the Saguaros facing a 6-3 deficit in the sixth, Olt struck again, belting a grand slam off reliever Daniel Meadows (Brewers).
"It was a 2-0 count again and he threw me a slider," said Olt, who will head home after the season to work with the coaching staff at his alma mater, the University of Connecticut. "I got a pitch over over the middle of the plate and I was able to hit it. I was able to react to that pitch up in the zone. That is something I've been working on."
The Rangers' No. 7 prospect, Olt leads the AFL with 11 long balls and 38 RBIs in 22 games. He has five homers and 15 RBIs in his last five contests and has hit safely in his last 12.
The 2010 first-round pick has three multi-homer games this fall after recording one in the Minor Leagues. He also has driven in at least five runs three times in the AFL, including a career-high six-RBI effort on Nov. 4 against the Javelinas.
Mets prospect Juan Lagares forged a 7-7 tie with an RBI single in the bottom of the sixth, but the Saguaros took the lead for good in the seventh as Christian Bethancourt (Braves) led off with his fifth homer. Matt Dominguez, the Marlins' No. 1 prospect delivered a two-run single in the eighth and Rays first-round pick Mikie Mahtook ripped a two-run homer.
The Javelinas answered with three in the bottom of the eighth on Lagares' bases-loaded double, then climbed within a run in the ninth on the strength of two singles, a double and an error.
However, with the tying run in scoring position and the potential go-ahead run at first, Royals left-hander Brendan Lafferty struck out Kentrail Davis (Brewers) and Marlins prospect Alejandro Ramos fanned Lagares to end the game and record his third save.
Making his first start as a pro and fourth Fall League appearance, Bradley struggled with his control. The 15th overall pick in this year's Draft gave up two runs on two hits and three walks while striking out a pair in 1 2/3 innings.
Braves Minor Leaguer Navery Moore (1-0) got the win, despite allowing a run on a hit and two walks while fanning two in two innings.