Connor Joe and Jack Suwinski hit back-to-back home runs in a four-run first inning Thursday to send the Pittsburgh Pirates on their way to a 4-3 win over the visiting Cincinnati Reds in a series opener.

The Pirates have won four straight and five of their past six.

Pittsburgh starter Roansy Contreras (2-1) allowed one run and five hits in 6 2/3 innings, with eight strikeouts and two walks. It was the team's 10th straight quality start.

David Bednar pitched a one-two-three ninth for his sixth save.

Jason Vosler and Jonathan India each hit an RBI single for the Reds, who have lost three in a row and four of five.

Cincinnati starter Luke Weaver (0-1), making his season and Reds debut after an elbow injury, pitched six innings and allowed four runs and four hits, with eight strikeouts and two walks.

In the first, Ke'Bryan Hayes led off with a single to left and Bryan Reyolds drew a four-pitch walk. After Andrew McCutchen grounded out and Carlos Santana struck out, Joe hit his second homer, a full-count blast into the bullpen in center, for a 3-0 Pittsburgh lead. Suwinski followed with his fifth homer, to right, to make it 4-0.

Weaver settled down after that, giving up only a one-out single to Austin Hedges in the second.

Cincinnati broke through in the seventh. Jake Fraley and Tyler Stephenson walked. Wil Myers grounded into a double play, with Hayes at third making a diving stop to his left to get the play started. That moved Fraley to third, and Vosler drove him in with a flare to shallow center to cut it to 4-1.

In the eighth against Colin Holderman, Jose Barrero reached on an infield hit. He went to second on Holderman's throwing error, reached third on a wild pitch and scored on India's base hit to right. TJ Friedl singled to right, and both runners advanced on a double steal. India scored on Spencer Steer's sacrifice fly to left, closing it to 4-3.

--Field Level Media