The first-time All-Star has come up with plenty of big hits lately.
Harrison and the Pirates try to keep pace in the wild-card race Saturday against the visiting Cincinnati Reds.
The Pirates (70-64) are seeking a season best-tying fourth consecutive win after sneaking by the Reds 2-1 on Friday. Pittsburgh surrendered the game's first run in the eighth before scoring twice in the bottom of the inning.
Keying the rally was Harrison, who delivered an RBI triple then scored the winning run on Jose Tabata's single to left. Harrison has hit .343 with eight extra-base hits - two homers - and seven RBIs in leading Pittsburgh to six wins in eight games.
"He's unbelievable," Friday's starter Edinson Volquez said of Harrison. "He can do everything. For me, he's the MVP with the way he's been playing. He's an exciting player."
Devin Mesoraco reached on a leadoff single in the seventh to break up Volquez's no-hitter as Cincinnati (65-70) finished with four hits. The Reds, who had won four of their previous five, have dropped six straight and 18 of 23 on the road.
The Pirates, meanwhile, are a major league-best 23-9 at home since June 19. They are just behind San Francisco and St. Louis for the top two spots in the wild-card standings.
Cincinnati's Alfredo Simon (13-8, 3.26) had gone 0-5 with a 5.40 ERA over a seven-start stretch since the break before beating Atlanta 5-3 on Sunday. The All-Star right-hander allowed five hits over seven innings of one-run ball while striking out six and walking one.
"Simon was ahead in the count and was able to use his whole complement of pitches," manager Bryan Price said. "There are times when a pitcher is throwing with the same velocity but it doesn't feel like it. He tries to manufacture more. Today, he just executed his pitches."
Simon has defeated the Pirates twice in as many tries this year while holding them to a .188 average. Andrew McCutchen is 2 for his last 12 with a homer when facing Simon while Russell Martin and Neil Walker are a combined 0 for 13 since the start of last year.
Pedro Alvarez has also struggled, going 1 for 10 in their matchups. His status remains unclear after missing the last two games a with foot injury.
Pittsburgh gives the ball to Vance Worley (5-4, 3.14), who has posted a 6.11 ERA over a career-worst three-start losing streak. The right-hander was tagged for four runs and a season-high 12 hits over 6 1-3 innings in Sunday's 4-3 defeat at Milwaukee.
Worley is 1-1 with a 5.21 ERA in four games - three starts - against the Reds. He gave up two runs and four hits over two innings in a 6-3 loss at Cincinnati on July 13 in his only relief appearance of the year.
Brandon Phillips is 4 for 8 against Worley but Jay Bruce is 2 for 10. Bruce is 4 for 29 with 13 strikeouts and no RBIs over his last eight games, and he's hitting .150 over a 25-game stretch against the Pirates.
Despite Friday's loss, Cincinnati is 9-5 in the series this year.