PHOENIX — Pavin Smith and Daulton Varsho have hit back to back in the lineup for a few seasons while coming up through Arizona’s system. But they had never hit consecutive home runs — until Wednesday.

And they picked a good time to do it: in the seventh inning of a tied game. Smith hit his ninth of the season and Varsho followed with his second, and the Diamondbacks held on for their fourth straight victory, 6-4 over the Pittsburgh Pirates.

“It finally happened,” Smith said. “We’ve been doing this for three, four years and always talked about it.”

Smith connected on a changeup from Duane Underwood Jr. (2-3) leading off the seventh to break a 4-4 tie, and Varsho followed with a blast to right against a fastball.

“They’re not missing the pitches they’re looking for,” Arizona manager Torey Lovullo said.

The Diamondbacks may have lost their hottest hitter, however. Lovullo said after the game that Josh Rojas has a dislocated left pinkie, suffered on a failed steal attempt in the eighth.

The finger was set back into place and Rojas was having tests after the game, Lovullo said. “We’re hoping for the best-case scenario and he’s day to day, but we’ll have to see.”

Rojas, who mostly plays second base but has seen time at shortstop and in the outfield, is batting .390 in his last 12 games for Arizona. He was 2 for 4 with a run scored, a double, a walk and a stolen base.

Nick Ahmed had three of Arizona’s 12 hits against six Pirates pitchers.

The Diamondbacks won their 30th game of the season — against an MLB-worst 68 losses — and their fourth in a row to match their season-best winning streak. They won four straight from April 18-22, including three games at Cincinnati which was their only previous sweep of the season.

Brett de Geus (2-0) walked John Nogowski to force in the tying run in the seventh after the Pirates loaded the bases on three singles against Joe Mantiply. But de Geus retired Jacob Stallings on a double play to end the inning.

“We got out of a bases-loaded jam,” Lovullo said. “It was real nice to see that type of success.”