OKLAHOMA CITY -- Bruce Chen finished off a scoreless spring and locked up a spot in the Baltimore Orioles' rotation in the process.

Chen pitched five scoreless innings and Luis Matos drove in the winning run with a triple in the ninth inning as the Orioles beat the St. Louis Cardinals 3-1 Friday night.

Matos drove in pinch-runner David Newhan with a triple to the gap in right-center off of St. Louis closer Jason Isringhausen, then scored when Mark Grudzielanek's relay throw hit him in the back as he slid into third base.

Chen, who was competing with Rick Bauer for the fifth spot in Baltimore's rotation, gave up only a single and a walk. He allowed only five hits in 14 2-3 scoreless innings this spring.

"He learned how to pitch," Baltimore manager Lee Mazzilli said. "The sequence was good, and he had good selection on how he pitched his guys. He has an idea of exactly what he wants to do. That's why he's my fifth starter."

It was Chen's first start of the spring after five relief appearances, but the 27-year-old left-hander said he felt he was ready to start every five days.

"I feel like my arm is strong enough and I feel like I'm going to be able to start," Chen said. "Whatever they want me to do, I'm going to help this team."

Chen finished last season in the Orioles' rotation after an August call-up from Triple-A Ottawa and went 2-1 with a 3.02 ERA in seven starts and one relief appearance. The Orioles are his seventh team in the past five seasons.

"It's always nice to be with one team and stick around," Chen said. "This is a very good opportunity here. I'm feeling good and throwing good."

Mazzilli said he told Chen he'd won the spot before the game. Bauer gave up five runs in four innings in Baltimore's 5-1 loss to St. Louis on Thursday.

"I was extremely happy," Chen said. "I prepared myself real well in the offseason so I could help this team win, and this is incredible for me."

The Orioles gave Chen the lead when Sammy Sosa led off the second inning with a single and came around to score on Jay Gibbons' double to the gap in left-center.

St. Louis capitalized on a lack of control by reliever Steve Kline -- who pitched for the Cardinals last season -- to tie it in the sixth. Kline beaned Larry Walker, who then advanced to second on a wild pitch and scored on a two-out single by Scott Rolen.

Jason Marquis pitched six solid innings in his final outing before starting the second game of the Cardinals' season-opening series against Houston. Marquis gave up one run on four hits in six innings. He struck out seven -- his most of the spring -- and walked one.

Notes: Brian Roberts, who missed Thursday's game with a bruised right shin, returned to the lineup and went 1-for-3 with a double and two walks. He was hurt Wednesday when he fouled a ball off his leg. ... Attendance was 13,066 -- a sellout at SBC Bricktown Ballpark, home of the Oklahoma RedHawks, the Texas Rangers' Triple-A affiliate. ... The Cardinals finish spring training with games Saturday and Sunday against their new Double-A affiliate in Springfield, Mo. Baltimore is off Saturday before concluding its spring at Philadelphia on Sunday.