JUPITER, Fla. -- Marlins ace Josh Johnson started earning his $39 million contract Saturday:~ Outfielder Colby Rasmus belted a home run in defeat

He struck out Albert Pujols looking to end a perfect first inning.

Making his first start since signing his four-year deal in January, Johnson allowed two earned runs in two innings in Florida's 6-5 win over the St. Louis Cardinals.

Johnson, who'll be Florida's opening day starter after posting a 15-5 record in 2009, was a little rusty in the second inning, which started with Colby Rasmus connecting on a 2-2 pitch for a long home run to right field.

Johnson gave up a single and a walk, and with two outs he struck out Tyler Greene. But the third-strike pitch got away from catcher Ronny Paulino, allowing Jon Jay to score from second base.

Florida Marlins starting pitcher Josh Johnson throws during the first inning of a spring training baseball game against the St. Louis Cardinals Saturday, March 6, 2010, in Jupiter, Fla. (AP Photo/Jeff Roberson)

He threw 14 pitches in the first inning, but needed 28 to get out of the second.

"My mechanics were a little bit off, a hair here, a little bit there," Johnson said after throwing 24 pitches for strikes. "I'll be ready for the [side session] to get the mechanics back going and to make sure I'm on top of everything."

Marlins manager Fredi Gonzalez was pleased with Johnson's outing.

"You know what? If I didn't know this was his first start of spring training, I would have thought it was the middle of the season," Gonzalez said. "His delivery, his command of his fastball, he was good."

Johnson's deal is the richest ever given to a Marlins pitcher by owner Jeffrey Loria. But he said he feels no pressure living up to any expectations.

"I've always had to just go out there and do my job, no matter what," he said. "It has always been the same and it'll always be the same."

Florida closer Leo Nunez made his debut and pitched a perfect ninth inning.

The Marlins won when Hector Luna, a nonroster invitee, singled to deep center with the bases loaded in the bottom of the 10th. It was the Marlins' second straight extra-inning win after beating the Mets 4-3 in 10 innings Friday.

Right-hander Kyle Lohse made his spring debut for the Cardinals and allowed one run on six hits in 2 2/3 innings.