ST. LOUIS (Interstat) — The Arizona Diamondbacks used a six-run fourth inning to break open a close game and beat the St. Louis Cardinals 9-4 on Wednesday night at Busch Stadium III, evening a three-game series at one win apiece.

Arizona, now 41-39, struck first with a pair of singles in the opening inning but could not score. St. Louis took a 1-0 lead in the bottom of the second when Blaze Jordan doubled to left field, driving in José Fermín, who had walked. The Diamondbacks responded with a six-run outburst in the fourth that turned the game decisively in their favor.

The rally began with Corbin Carroll singling off Cardinals starter Gordon Graceffo. Gabriel Moreno walked, and Nolan Arenado hit into a force out that left Carroll at third and erased Moreno. Tommy Troy then singled to right, the ball deflected by right fielder Jordan Walker, scoring Carroll and sending Arenado to second. Lourdes Gurriel Jr. popped out, but Ildemaro Vargas followed with a double to left that scored Arenado and Troy, making it 3-1. LuJames Groover then crushed his first home run of the season, a two-run shot to left field, and Ketel Marte capped the inning with a solo homer to left-center, his 13th of the year. By the time Geraldo Perdomo grounded out to end the frame, Arizona held a 6-1 lead.

The Cardinals answered in the bottom of the fourth. Fermín singled, Masyn Winn singled, and after Lars Nootbaar struck out, Jordan lifted a sacrifice fly to center that scored Fermín, cutting the deficit to 6-2. Neither team scored in the fifth, and Arizona added two more in the seventh. With one out, Moreno walked, and after Arenado grounded out, moving Moreno to second, Troy hit a ground-rule double to right-center, scoring Moreno. Gurriel Jr. followed with a double to left that plated Troy, pushing Arizona’s lead to 8-2.

Arizona added another run in the eighth. Groover walked, Marte singled, and Perdomo reached on a fielder’s choice that loaded the bases when a throwing error by third baseman Blaze Jordan allowed Groover to advance. After Carroll struck out, Moreno lifted a sacrifice fly to left that scored Groover, making it 9-2.

The Cardinals mounted a brief rally in the ninth. With one out, Fermín hit his third home run of the season, a solo shot to left. Masyn Winn grounded out, but Nootbaar tripled on a sharp fly ball that was deflected by center fielder Jorge Barrosa. Blaze Jordan then singled to center, scoring Nootbaar to make it 9-4. Alec Burleson flied out to left, and JJ Wetherholt grounded out to end the game.

Arizona’s six-run fourth inning was the decisive sequence, turning a one-run deficit into a five-run lead that St. Louis could not overcome. Groover’s two-run homer and Marte’s solo shot were the key blows in that frame, and Troy and Gurriel Jr. drove in runs in the seventh to put the game out of reach.

Ryan Thompson earned the win for Arizona, improving to 3-1 on the season. He allowed two runs on four hits over five innings, walking two and striking out four. Matthew Liberatore took the loss for St. Louis, falling to 3-5. He surrendered six runs on six hits in three-plus innings, walking two and striking out two.

Arizona’s offense amassed 12 hits. Marte had two hits, including a home run and a single. Troy had two hits, a double and a single, and drove in two runs. Gurriel Jr. also had two hits, including a double, and drove in a run. Groover had a home run and a walk. Arenado doubled. Vargas doubled and drove in two runs. Carroll and Moreno each had a single, and Moreno added a sacrifice fly.

St. Louis managed eight hits. Jordan led the Cardinals with two hits, including a double and a single, and three RBI. Fermín had two hits, a home run and a single, and drove in a run. Nootbaar tripled. Burleson singled. Walker singled. The Cardinals left six runners on base.

The game was played before a crowd of 22,376. Time of game was 2 hours, 54 minutes.

Arizona evened the series after losing the opener 3-2 on Monday and winning 4-3 on Tuesday. The Diamondbacks have won two of their last three after dropping three straight to the Minnesota Twins at home. St. Louis had won the first game of the series but fell to 42-36, losing for the third time in four games.

Wednesday’s result was notable because Arizona had been installed as a pregame favorite with a spread of minus-1.5 runs. The Interstat game simulator had projected a final score of St. Louis 6, Arizona 5, and the Interstat ELO system gave the Cardinals a 54.20 percent probability to win. The combined total of 13 runs went under the over-under line of 8.5.

The Diamondbacks conclude the series Thursday afternoon before traveling to Tampa Bay for three games. St. Louis remains home to open a three-game set against the Miami Marlins on Friday.