ANAHEIM, Calif. -

Mike Trout described his first major league grand slam as "just another home run."

Teammate Garrett Richards was pretty grateful just the same for the nine-run first inning to support him against Detroit's Rick Porcello.

Trout's second homer of the season capped the Angels' most productive first inning in almost 18 years, and Richards pitched two-hit ball over seven innings in a 10-0 romp over the defending AL champion Tigers on Saturday.

"It's always good to help your starter out like that. Then they can pound the strike zone and not have to worry too much," Trout said. "We're looking better, stating positive, grinding it out and having great at-bats."

Richards (1-0) struck out eight and walked none. Prince Fielder's leadoff single in the second and Miguel Cabrera's leadoff double in the seventh were the only hits off the right-hander in his second start for the injured Jered Weaver, who is sidelined with a broken bone in his non-pitching arm.

"I don't pay attention to the score. I try to pitch the same, whether it's 9-0 or 0-0," said Richards, who left the dugout during the long inning and played catch with backup catcher Hank Conger in the indoor batting cage to stay loose. "Those kinds of games are a little bit harder to pitch in, just because you don't want to relax. You want to keep going after guys. I stayed aggressive and kept attacking guys."

Richards has pitched into the seventh inning in both starts — the only one on the staff to make it past the sixth in the team's first 16 games.

"He threw 94-97, and his fastball moves in three different directions, so we don't really know which way it's going to go," catcher Chris Iannetta said. "The hitters don't know either."

The Tigers, who lost Friday night's series opener 8-1, were shut out for the third time this season and have scored three runs in their last 42 innings — two of which came on groundouts.

Porcello (0-2) faced 11 batters, threw 47 pitches and got only two outs — on a double-play grounder by Iannetta. The right-hander, who gave up an AL-worst 226 hits last season en route to a 10-12 record, has allowed 16 earned runs in 11 innings over his first three starts for a 13.09 ERA.

Albert Pujols singled with two men on to drive in the Angels' first run of the game and Josh Hamilton walked to load the bases before Mark Trumbo singled in the second run and Howie Kendrick added two more with another single.

"We really had the same plan we usually take, staying up the middle and waiting for our pitch," Trout said. "That was our main thing. When Trumbo hit the bases-loaded single and Howie came up with the two-run single, it was big just to keep the inning going for us."

Brendan Harris delivered the fifth run with a two-out single, and the Angels loaded the bases again with infield hits by Luis Jimenez and Peter Bourjos.

Trout then drove a 1-2 curveball into the trees beyond the center field fence. Detroit manager Jim Leyland finally replaced the shell-shocked Porcello with Drew Smyly, who gave up a double to Pujols before retiring Hamilton on a flyball.

"I struggled a little bit with my command, but it wasn't all that bad," Porcello said. "I think we've all had games where guys are hitting the ball hard against you, but right at people. You cruise through seven innings and you walk away feeling pretty good about it — even though you didn't throw the ball that well. Today I felt like I threw the ball fine. I did the best I could, but it just wasn't in the cards today."

The 10 first-inning hits set an Angels franchise record. It was their highest scoring inning since a nine-run sixth at Texas on July 30, 2012, and their most productive first inning since they started with 11 runs June 29, 1995, also at Texas.

Trout, last season's AL rookie of the year, has nine RBIs over his last three games after driving in only two in his first 13. Last year he didn't get called up from the minors until April 28, and still finished with 30 home runs, 83 RBIs, a .326 average and a league-high 129 runs scored in 139 games.

NOTES: The Angels' previous record for first-inning hits was eight, against Oakland's Chris Codiroli on July 30, 1983. ... The 18 runs scored by the Angels during the first two games in this series were four more than Detroit's pitchers had allowed over their previous seven games combined. ... Bourjos drove in the final run with a sacrifice fly in the eighth and ended up with three infield hits. Two seasons ago he had 36 infield hits, fourth-most in the AL. ... Trout's previous 10 home runs all were solo shots. ... Smyly allowed four hits through 5 2-3 innings, his longest outing since a six-inning start against the Angels last Aug. 25. ... Angels RHP Mark Lowe, who has allowed eight runs, eight walks and four hits in 6 1-3 innings of relief, was placed on the 15-day disabled list. ... INF Tommy Field, claimed off waivers by the Angels from Minnesota in November, was recalled from Triple-A Salt Lake. He has 18 games of big league experience, all with the Colorado Rockies.