ANAHEIM -- The education of Joe Saunders continued Tuesday night, and his efforts have earned more than a passing grade.

The left-hander has been a mainstay of the Angels rotation on the young season and he is quickly laying claim to the mantle of staff ace in the absence of right-handers John Lackey and Kelvim Escobar, both of whom are residing on the disabled list.

Saunders carried his burden efficiently and with great ease as he was given the ball in his start against the A's, turning in eight scoreless innings to groove the Angels to a 2-0 victory.

That performance elevated his record to an unblemished 5-0 in six starts for the year and put him on a par with Frank Tanana as the only Angels pitchers to post five wins without a loss in the month of April. The fellow southpaw did so in 1978.

"That's nice. To be in that kind of company is an honor," Saunders said. "I'm proud of myself that I was able to do that."

About the only thing lacking in Saunders' outing was not going the distance. But manager Mike Scioscia said the cool evening and the fact his starter had thrown 102 pitches was reason enough to hand the ball to closer Francisco Rodriguez.

The closer survived a pair of ninth-inning walks and was aided by two outstanding catches by Erick Aybar, one on a popup in shallow center and another on a foul ball down the left-field line that the shortstop ran down by racing between third baseman Brandon Wood and left fielder Gary Matthews Jr. for the out to end the game.

"Erick is showing the potential that everyone knew he had," Scioscia said. "He's bringing it. His range is incredible. The popup that he caught in center field was not easy, and the one he caught going down the line shows his range. He's making the plays at shortstop from the routine to the outstanding ones."

Saunders was paced by a pair of third-inning runs, pushed across on a wild pitch and a ground ball. Not exactly evident of the Angels' AL-leading .989 slugging percentage entering Tuesday's contest, but Saunders was able to make the most of his team's three hits.

He was at his shakiest, if that critique is fair, in the first couple of innings when the A's recorded one of their four hits against him on Mark Ellis' first-inning single. But the Oakland second baseman was erased in a rundown after Saunders threw over to first.

From there, the A's hit five straight fly-ball outs. But that also established a groove for Saunders, who retired a total of nine straight before allowing a two-out single to Mike Sweeney in the fourth.

Saunders continued to roll and didn't allow two baserunners in any one inning, allowing a two-out walk in the fifth, a one-out single in the sixth and a leadoff single in the eighth. With strong defense, Vladimir Guerrero ran down a fly ball in the seats in foul territory in right to end the sixth, Saunders was able to stay ahead of most of the A's hitters.

"About the fourth or fifth, I kind of locked myself in," Saunders said. "[A's starter Greg Smith] was throwing well, too, and I needed to throw up as many zeros as he was."

Smith (2-1) held the Angels in check for most of the night and made his only real mistake when he uncorked a wild pitch in the third inning and ultimately took the complete-game loss.

With one out, Wood walked on four pitches and Chone Figgins followed with a double down the right-field line. Smith threw a pitch in the dirt that skipped between the legs of A's catcher Kurt Suzuki and Wood scored.

Matthews followed with a ground ball to short to bring home Figgins and the Angels took what proved to be a commanding 2-0 lead.

"I thought Greg Smith pitched an excellent game, but Saunders was just a touch better," A's manager Bob Geren said. "[Saunders] has a real nice fastball-changeup combination, in any count, and he didn't leave many balls over the plate. He pitched very, very well. ... He just really had a nice hard-soft game, and great location."

Saunders split time between the Angels and Triple-A Salt Lake last year, starting 18 with the big club and another 14 in the Minors. As good as he's going, he knows what is needed to stick around.

"They say in high school that it's harder to stay in the big leagues than to get there," Saunders said. "It's humbling. Even though I was pitching well last year, I was sent down. But you have to look at the company I was with, I was taking the spot of a Cy Young Award winner [Bartolo Colon] and I knew my role."