"It was a good way to start, for sure," Montgomery said. "It was exciting … my first Opening Day."
One of the questions the Mariners face is to see how quickly Montgomery can bounce back in a relief role.
"I'd like to give him a day after a couple-inning outing like that," manager Scott Servais said prior to Tuesday's game. "But when they pitch that well, you want them available as often as possible. He was a really, really bright spot in [Monday's] game. I couldn't be any happier for him."
Montgomery, who is out of Minor League options and didn't have much of a shot to land a job in the rotation with the six candidates ahead of him all staying healthy through camp, still believes he's capable of being a quality Major League starter, but he's happy to have a place with the Mariners as they open the season.
"I'm whatever they want me to be," Montgomery said. "I think I can get the job done, for sure. I feel comfortable. I've been doing it for almost a month now. Some of those things anyone is going to have to deal with, whether it's nerves or how much time you need to get ready."
Servais said he'll be careful with how often he asks Montgomery to get up in the bullpen initially, knowing that the routine is new to him.
Montgomery acknowledged he was "a little too amped" when he initially started warming up Monday when Hernandez started struggling in the fifth, but benefitted from being told to sit back down after the Mariners ace regained control and worked through the sixth.
"It's definitely a little different," Montgomery said. "It's a lot harder to control your adrenaline. You have to get ready quick and you have to get the guys out that you face."
Montgomery isn't totally buying the notion that he's throwing better now, given the ability to throw harder and let everything rip in shorter bursts. He says he came to camp throwing well as a starter and is just continuing that path now in his new role.
"I felt like in the offseason I really refined some of my offspeed pitches and got a little stronger and my fastball got a little bit better as well," he said. "I felt that way going into spring. But coming in for one or two innings, you do know you can let it go a little bit more."
Greg Johns is a reporter for MLB.com. Follow him on Twitter @GregJohnsMLB, read his Mariners Musings blog, and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.