Three times in the first five innings, he faced Tigers cleanup hitter Miguel Cabrera with at least one man on base. Cabrera, who entered batting .455 with two homers and five RBIs, was retired each time.
In the third, Cabrera came up in a 1-1 game with runners on second and third and two outs. Arrieta could have pitched around him or walked him, but instead got him to line out to left.
"Not really wanting to work around him, but we know he's a good hitter that we don't want to beat us in a spot like that," Arrieta said. "The emphasis is really on quality pitches rather than pitching around him. Want to pitch to our strengths. We've had some success against him in the past."
Fueled by that escape, the right-hander went on to allow six hits and one run over six innings to get the win. O's starters now have an ERA of 0.69 during the 4-0 start.
"It's one of those things, where you want to follow (the other starters') lead. They set the tone the first three games. I think we all feed off of each other and it builds confidence with each quality outing.
"I knew today was going to be tough emotionally. I told (bullpen catcher) Ron (Deck) to run in there and grab me a bottle of water when I was warming up. I had the worst dry mouth I think I've ever had. I don't think there's a better feeling in the world, then the feeling you get when you toe the rubber on opening day in your home stadium."
Arrieta said he fed off the sellout crowd of 46,593.
"The crowd was electric. The emotions were high. There's not a better feeling. It was great, a great day," he said.
Over his last four starts, dating to last season, Arrieta is 3-0 with an ERA of 2.31.
"We're aware of the talent we have. If we pitch and keep our team in the game, it's only a matter of time before we put some runs on the board," Arrieta said. "It may be two, three, four guys a night with the quality hitters we have.
"It's fun to be a part of this team right now and I'm real excited by the direction we are going."