Nick Tropeano helps deliver a 4-1 victory for the Angels over the Athletics

The starting pitchers had combined to throw 155 pitches in a scoreless tie into the sixth inning Monday. Much of the typically fierce Oakland Coliseum crowd had been lulled to sleep, the same state the Angels’ offense occupied for the season’s first week.

And then, at once, the game between the Angels and Oakland Athletics came alive. Yunel Escobar laced a one-out double off the right-field wall. On Sonny Gray’s next offering, Daniel Nava singled to center, driving in Escobar. Mike Trout slammed Gray’s proceeding pitch to straightaway center field, at least 420 feet, well beyond the fence in this football stadium-turned-ballpark.

On three pitches, the Angels had three runs. There would be only one more for each team, as the Angels secured a comfortable 4-1 victory and moved to 3-4 on the budding season behind a solid start from young Nick Tropeano.

“Tropeano and Sonny were cruising,” Trout said. “We were just trying to get something started.”

Said Angels Manager Mike Scioscia: “That inning was important to us.”

Tropeano turned in the best start the Angels have had in 2016, striking out six Athletics while walking two and scattering six hits in five innings. The 25-year-old right-hander is in the majors only because left-hander Andrew Heaney had to be put on the 15-day disabled list last week. He should have at least three more starts to prove he deserves to stay.

He exited Monday’s start after walking Stephen Vogt to begin the sixth. Fernando Salas served up a double-play ball and saved Tropeano, and the Angels asked left-hander Jose Alvarez to toss 12/3 innings before giving way to Joe Smith and then Huston Street in the ninth.

Smith permitted the lone run on two singles before Street quickly warmed, entered and recorded the final out for the save. Until the ninth, it was an altogether smooth affair, considering the Angels had to face Oakland’s ace in the first game of a three-city, 10-game trip. They won’t face another accomplished starter in Oakland or Minnesota until at least Sunday.

During their season-opening six-game homestand, the Angels mustered only 12 runs. It seemed their offensive woes would continue until the sixth-inning outburst.

Trout worked his fifth walk of the young season in the first inning but was stranded after Albert Pujols flied out to center on the next pitch. In the second inning, Kole Calhoun singled and then was erased on his own volition, caught trying to steal second base with C.J. Cron swinging and missing a Gray fastball.

The Angels botched an Oakland hit-and-run in the third inning. Josh Reddick took off running from first, and Danny Valencia singled through to right field. Calhoun threw to third to try to get Reddick, but Andrelton Simmons cut it off and threw to first, where Valencia appeared caught off the base. Pujols and Cliff Pennington could not coordinate their subsequent throws and Valencia reached second safely. Fortunately for them, Tropeano induced a pop-up from Vogt to end the inning.

He also worked out of trouble when a Coco Crisp drive bounced off Calhoun’s glove in right for a triple in the fifth.

Pujols stole the Angels’ final run in the eighth. After he singled off Oakland reliever Liam Hendriks, he caught Hendriks forgetting him and stole second standing and without a throw. Cron grounded him over to third and Simmons singled him home.

Improbably, the plodding Pujols became the only Angel to steal a base this season. Scioscia called that fact a “little ironic.” Trout asserted that teams cannot leave his teammate alone on the bases, for the 36-year-old still has “some speed.”

Pujols laughed and then grinned when questioned about it.

“I put my cape on,” he said.

pedro.moura@latimes.com

Twitter: @pedromoura