WASHINGTON -- After the skies opened up Thursday afternoon at Nationals Park, the Nats’ bullpen was left with 8 2/3 frames to cover in the 10-inning series finale against the Reds.

By the end of the Nationals’ 5-4 loss, seven pitchers had taken the mound for Washington. That tied the team’s season high set on July 1, when utility man Ildemaro Vargas pitched in a lopsided loss to the Phillies.

“It starts with the first guy [out of the bullpen] and wondering how far he can go,” manager Dave Martinez said. “Mason [Thompson] did a great job, he really did. You’re hoping for an inning and two-thirds, and he gave us more than that. So that set the tone. Then the rest of the guys just followed suit. I thought they did really well."

Starter MacKenzie Gore’s day was cut short after 1 1/3 frames following a one-hour, 43-minute rain delay. The southpaw continued to throw in the bullpen as the rain poured down on the field, but the Nationals cut off his potential to return at around 50 minutes given last season’s injury history.

“MacKenzie’s a competitor, and he’s one of the most competitive guys on the team,” said catcher Riley Adams. “You saw him kind of slowly walk off the field once they called to bring the tarp on, and that just shows how bad he wanted to stay out there.”

The Nats tabbed Thompson to resume the game with one out and Elly De La Cruz on third base. Thompson quickly escaped the jam by getting Tyler Stephenson to ground into a double play. With his effectiveness, Thompson was able to cover 2 2/3 innings (one run on one hit and one walk).

“My favorite part about it is, you don’t think about it -- you just go out there and do it,” Thompson said. “No time to think, just go compete. Today, I didn’t feel sharp, but I was able to get the job done.”

Jordan Weems delivered 1 2/3 frames (one run on no hits, one walk and one hit-by-pitch with two strikeouts), and No. 24 Nationals prospect Jose A. Ferrer pitched 1 1/3 scoreless innings with only one hit. Since his Major League debut on July 1, Ferrer has made four relief appearances without allowing a run.

“He keeps his poise out there,” said Martinez. “The big thing is, though, he’s throwing strikes, and that’s awesome. He’s got a good two-seamer right now. It’s working.”

With the Nationals leading, 3-2, in the eighth, Kyle Finnegan allowed one run on two hits to even the score. Hunter Harvey (three strikeouts in 1 1/3 innings) posted zeros in the ninth to help push the game to extra innings, but he gave up a two-run homer to Nick Senzel to give the Reds the advantage in the 10th.

“I just left the pitch in the middle of the plate, and he hit it,” Harvey said, adding, “Mason, Weems, Ferrer -- they kept us in the game. Back end, we didn’t do our job today, and it’s what happens.”

Cory Abbott closed out the 10th with a walk and two strikeouts in two-thirds of an inning.

“The guys stepped up, for the most part,” Martinez said. “Abbott, who was on just a day’s rest, comes in and finishes the game for us, which is great. The big question is tomorrow. We’ll see how everybody is tomorrow.”

Behind the plate for all seven pitchers was backup catcher Adams, whose daily studying had him prepared for the multitude of changes in pitching plans.

“It’s just knowing your guys. I think Keibert [Ruiz] has done a good job this year trying to work with our pitchers and game plan the strengths of each guy and how we can get guys out,” Adams said. “... Obviously, it’s a weird game with the delay so early, and you’ve just got to be ready for that.”