CINCINNATI (Interstat) — The playoff-bound Chicago Cubs, riding a three-game winning streak, open a pivotal four-game series against the Cincinnati Reds on Thursday night at Great American Ball Park.

The Cubs (88-65) arrive in Cincinnati fresh off a three-game sweep of the Pittsburgh Pirates, including an 8-4 victory on Wednesday powered by Ian Happ’s three RBIs. Chicago has won seven of its last 10 games as it battles for a postseason berth.

The Reds (77-76), meanwhile, are looking to play spoiler after splitting a two-game set with the St. Louis Cardinals. Cincinnati took the Wednesday finale 6-2 behind a monster performance from Spencer Steer, who went 3 for 4 with a home run and five RBIs.

This season series has been a back-and-forth affair. The clubs last met in early August at Wrigley Field, where the Cubs took two of three. Their previous encounter in late May saw the teams split a six-game slate that featured high-scoring affairs, including a 13-6 Cubs win and an 11-8 victory for Chicago.

Despite the Cubs holding the better record and recent form, sportsbooks have installed the Reds as a slight pregame favorite with a spread of -1.5. The over/under is set at 9 runs. However, Interstat’s metrics project a close Cubs victory, with a final score of 6-5 and gives Chicago a 55.4% probability to win.

The series is critical for the Cubs, who follow this set with three games at home against the New York Mets and three more against the St. Louis Cardinals to close the regular season. Every contest is magnified in their push for October baseball.

The Reds, sitting just below .500, will look to disrupt those plans before hosting the Pittsburgh Pirates next week. First pitch is scheduled for 6:40 p.m. EDT.