Harrison had three hits while also making a number of sparkling defensive plays. Tabata, starting in right field for the injured Travis Snider, finished with two hits in the Pirates' sixth win in eight games.
"He's unbelievable," Volquez said of Harrison, who began the season as the last man on the Pirates' bench but is now their leadoff hitter. "He can do everything. For me, he's the MVP with the way he's been playing. He's an exciting player."
Volquez was working on a no-hitter before Devin Mesoraco's leadoff single in the seventh. He was charged with one run and three hits in 7 2/3 innings, running his unbeaten streak to seven starts.
"It was a very impressive outing," Pirates manager Clint Hurdle said. "It wasn't his best fastball but he kept it down and no-hit them for six innings without the best stuff we've seen from him."
Reds right-hander Mike Leake allowed six hits in seven innings in his second consecutive scoreless outing. He pitched 6 2/3 innings in a 1-0 victory over Atlanta last Saturday in his previous start.
Cincinnati put two runners on in the eighth, chasing Volquez from the game. Mesoraco then put the Reds in front with an RBI single against Tony Watson (10-1), but Brandon Phillips was thrown out at home to end the inning.
The Pirates' ERA is 2.15 over their last eight games.
Mesoraco had two of the Reds' four hits.
The Pirates' winning rally came against Jonathan Broxton (4-2).
"It was really one pitch that hurt me," Broxton said. "Harrison hit one off the right-field wall but the other two hits were ground balls."
Reds: 1B Joey Votto experienced pain in the area of his troublesome left knee on Wednesday when he attempted to field ground balls for the first time since going on the disabled list July 6 with a distal quadriceps strain, manager Bryan Price said Friday. Votto won't be ready to play when he is eligible to come off the disabled list on Thursday, and the rest of the season is in doubt.
Pirates: 1B Pedro Alvarez (sprained left foot) sat out for a second game and Snider (left hamstring discomfort) was not in the lineup after leaving Wednesday's win over St. Louis. Both are day to day.
Reds: RHP Alfredo Simon (13-8, 3.26 ERA) will start Saturday in his first outing since breaking a five-game losing streak Sunday by beating Atlanta. Simon is 1-4 with a 4.74 ERA in eight starts in the second half after going 12-3 with a 2.70 ERA in 18 starts in the first half and being selected to his first All-Star game.
Pirates: RHP Vance Worley (5-4, 3.14 ERA) will try to bounce back after losing his last three starts and compiling a 6.11 ERA in that span.
BOLSTERING THE BENCH
The Pirates recalled Lambo to bolster their bench with Alvarez and Snider sidelined.
Lambo hit .328 with 11 home runs and 42 RBIs in 61 games at Indianapolis. He also had hit six home runs in his last eight games.
RHP Gerrit Cole was optioned to rookie-level Bristol to clear a roster spot for Lambo. However, it is strictly a procedural move and Cole will be recalled Monday when the roster limit expands to 40 and start that day at St. Louis.