It wasn't so much the heat that was getting to Chen, but the amount of ground-ball outs the left-hander was getting in the Orioles' 4-0 victory over the Phillies at Oriole Park at Camden Yards.
"Maybe my pitch selection was a little bit different than my previous games," Chen said through an interpreter. "With so many ground balls in the infield, I had to run so many times."
Chen recorded just three outs that weren't on the ground or by strikeout in his eight-inning performance. He allowed just four hits and one walk, while tying a season-high with nine strikeouts for his eighth quality start -- the most by an Orioles starter this season.
The left-hander's first scoreless start of the season -- and first since Sept. 5, 2014, at Tampa Bay -- was also the Orioles' first game since May 29 where a Baltimore starter went more than seven innings.
"He was ready to go from the get-go, as you could see," Orioles catcher Matt Wieters said. "From his last start, he wanted to get deep in the game. He came out there with a plan and he carried it out."
Chen did not allow a hit until the fourth inning, and he kept Phillies hitters on edge with his offspeed pitches. Wieters and Orioles manager Buck Showalter both mentioned how good Chen's slider was on Monday, which is something the lefty said he's spent a lot of time working on in the bullpen.
"He can command his fastball to both sides of the plate, but it gives him something that's not on the same plane," Showalter said. "When you can go a different speed and a different plane, it bodes well for you."
For as good as Chen was on Monday, and has been at most times during this season, he boasts just a 3-4 record. The lefty picked up his second win at home this season, but he was happy to exit to the game to a standing ovation.
"It's been a while since I had that, so yes, I feel great," Chen said.
Connor Smolensky is an associate reporter for MLB.com.