The Cardinals trailed 4-2 in the bottom of the seventh when pinch-hitter Kolten Wong, who didn't start the game after injuring his head on Sunday, hit a two-run homer to right to tie the game. Jon Jay then tripled, spelling the end of Gerrit Cole's outing.
John Axford took his place on the mound and walked Oscar Taveras to bring up Holliday, who ripped a grounder through the hole on the left side to plate Jay.
The base hit gave Holliday his third RBI of the contest. The slugger drove in five runs in Saturday's rout of the Cubs and four more on Sunday, including the game-winning two-run single in the eighth. He has 16 RBI in his last eight games.
The Cardinals, who entered the day tied with Milwaukee for first place in the division, extended their lead over the Pirates to three games. The Brewers are also a game back now after falling to the Cubs.
Lance Lynn gave up three runs on eight hits in six innings for the Cards, winners in three straight following a four-game slide. Seth Maness (6-3) picked up the win after finishing the seventh inning. Trevor Rosenthal nailed down his 41st save with a clean ninth.
Cole (7-5) surrendered five runs on eight hits in 6 1/3 innings. Andrew McCutchen hit a solo homer, while he and Josh Harrison each had two hits and two runs. Neil Walker drove in two in the setback.
Harrison led off the game with a single and McCutchen put the duo in scoring position with his ground-rule double. Walker gave the Pirates an early 2-0 lead with his two-bagger to center.
Andrew Lambo doubled home Harrison an inning later to make it 3-0, but St. Louis closed the gap in the third. Lynn singled and Taveras walked for Holliday, whose two-run double had the Cards within a run.
McCutchen's solo shot off Kevin Siegrist in the seventh made it 4-2.
The Cardinals are alone in first place for the first time since July 20 ... Since 2011, the Cardinals are a major-league best 53-28 in September ... Both teams had 10 hits ... Prior to the game, the Pirates recalled Gerrit Cole from Bristol of the Rookie League, activated pitcher Stolmy Pimentel from the 15- day disabled list, recalled catcher Tony Sanchez from Triple-A Indianapolis, selected the contract of pitcher John Holdzkom and optioned him to Indianapolis and designated first baseman Chris McGuiness for assignment.