The 6-foot-9 righty, who made his Major League debut Sunday afternoon, tossed six innings en route to a 6-2 victory over Baltimore. The win gave the Rays the three-game series, the first series win for the team this year.
Niemann got into trouble early, throwing 28 pitches in the first inning and loading the bases with one out, but he persevered, getting Baltimore's No. 5 and 6 hitters to pop up and fly out, respectively, squelching the threat.
"It was huge," Niemann said, about getting out of early trouble. "[There] definitely was luck involved, but I'm glad I was on the good side of it."
The righty went on to retire the next four batters he faced, and he had exceptional command of his fastball, fanning five and allowing only one walk.
"Jeff was very impressive today," manager Joe Maddon said. "Being able to throw a strike with a breaking ball when you're down in the count in the American League is huge."
Maddon went on to praise Niemann's composure in the game's early innings.
"He had a good look about him," Maddon said. "He was very confident going into the game."
The 25-year-old got the start in place of Matt Garza, who left Tuesday's game with radial nerve irritation in his right arm and is currently shelved on the 15-day disabled list.
Although Baltimore had a leadoff hit in three of the first five innings, the Rays were buoyed by strong defense from Carl Crawford and gritty throwing from Niemann, who was especially commanding with Orioles runners in scoring position.
"You've got a guy making his first start, and you've got him on the ropes in the first inning and playing like we did last night, coming to get them in the ninth inning," Orioles manager Dave Trembley said. "It would have been to our advantage to jump on him in the first. We didn't do it. [We] let him off the hook."
Niemann's only hiccup of the day came in the sixth inning, when Nick Markakis sent the first pitch of his at-bat sailing over Crawford for a solo homer in the sixth inning. The righty then hunkered down, sandwiching a pair of strikeouts around Luke Scott's double to force the Birds to strand their sixth batter in the same number of innings.
After four hitless innings, the Rays finally gave Niemann some breathing room in the bottom of the fifth, when they exploded for six runs off Baltimore starter Brian Burres.
Longoria opened the inning with a leadoff walk, before consecutive line-drive singles from Justin Ruggiano and Mike DiFelice loaded the bases. Akinori Iwamura and Crawford delivered another pair of left-field singles to put the Rays up three.
But the bats weren't finished yet. B.J. Upton took a full-count pitch from Burres over the left-field fence, plating another trio of runs. Upton's homer would come on the final pitch of the day for Burres, who was yanked with two outs in favor of Randor Bierd.
"I've been hearing all week, 'Your brother's got five and you haven't even gotten on the board yet,'" Upton said, referring to his power-hitting younger brother, the Diamondbacks' Justin Upton.
"It's tough not to think about it, but I've been scuffling a little bit, and we've been scuffling as a team," he added. "So I had some good at-bats and happened to run into one."
After lefty J.P. Howell loaded the bases in the bottom of the seventh, the Rays turned to Dan Wheeler to get out of the jam. The right-hander faced just one batter in Saturday night's game, allowing a game-winning solo home run to Ramon Hernandez in the ninth inning. There were no hints of carryover, however, as Wheeler got the first two outs of the inning, including a strikeout to cleanup hitter Kevin Millar. Lefty specialist Trever Miller sent former Ray Aubrey Huff packing on three pitches for the final out.
Maddon had little doubt about putting Wheeler in again, saying it was good to get him in "an even more heated situation." Wheeler was admittingly more cautious this time around, saying he was particularly careful with Markakis, who flied out.
"I want to save the game ultimately," he said. "A big league hitter is a big league hitter."
And after Sunday, Niemann is officially a big league pitcher.
"There's no preparing for your first Major League game, especially for a starting pitcher," DiFelice said. "I can't say enough about how he handled that first inning. Then he got on a nice little roll. [I'm] really impressed with how he pitched today."
Even a postgame beer shower from his team couldn't wipe the grin off of Niemann, who also received a bottle of Dom Pérignon from teammate Cliff Floyd.
"Never tasted better," Niemann said of the dousing. As for the champagne? "I might not open this one," he said.
Better to save it for the things to come.
Brittany Ghiroli is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.