PHILADELPHIA -- With one out remaining in the sixth inning, a large contingent of the 30,423 fans at Citizens Bank Park exploded into a standing ovation as the Philadelphia Phillies' starting pitcher left the mound.

Their cheers were for 25-year-old rookie Adam Morgan, who led the Phillies to a 9-2 victory in a successful debut over the major league-leading St. Louis Cardinals, salvaging the series finale on Sunday.

Morgan (1-0), who was notified late in the week that he would be moving up from Triple-A Lehigh Valley to replace right-handed pitcher Seth Rosin, threw 5 2/3 innings and got some much-needed offense from a lineup that had been struggling for weeks.

"When I got taken out in Lehigh after the two innings (last Wednesday), they said they were managing my innings," Morgan said. "They did a good job of playing it off, so I didn't want to think too much ahead.

"I was confused at it, but they told me a couple days later what their reasoning was, and it made sense. But I didn't want to look ahead."

The rookie right-hander allowed just one run on six hits and struck out six batters on 78 pitches, 54 of which were strikes, becoming the first Phillies starter to earn a win since May 23, a franchise-worst span of 25 starts without a victory for the rotation.

The Phillies' offense made it easy for him, scoring more runs than they had in any game thus far on the season.

After Morgan served up two scoreless innings to start his major league career, the Phillies (24-47) hit the scoreboard first in the bottom of the second inning in a big way, scoring three runs on Cardinals starter Michael Wacha (9-3, 2.85 ERA).

The big blow was a two-run, bases loaded single by second baseman Cesar Hernandez.

Morgan's lone blemish on his impressive debut came in the top of the fourth, when Cardinals shortstop Jhonny Peralta homered off the rookie for his 11th home run of the year.

"I'd say he earned another start, we haven't talked about when that would be," Phillies manager Ryne Sandberg said. "We do have a day off coming up, we'll talk about that. He was impressive today, it was fun to watch."

Things got worse for the Cardinals (45-24) in the bottom of the fifth, as they saw their 3-1 deficit increase to 5-1 by the inning's end thanks to RBI base hits by Phillies third baseman Maikel Franco and first baseman Ryan Howard.

Wacha, who made it into the seventh inning in five of his last six starts, picked up his third loss of the season, tossing 81 pitches (57 strikes) through five innings of work while allowing five earned runs on eight hits, one walk and seven strikeouts.

"One of those days, you know," said Cardinals manager Mike Matheny. "He, at times, would find the feel for it and then he was having trouble early on establishing the bottom of the zone with the fastball missing low, getting into hitter's counts having to challenge and they were finding a good part of the bat."

The Phillies tacked on some insurance runs in the bottom of the sixth and seventh by way of an RBI single by outfielder Ben Revere and a three-run home run from infielder Andres Blanco.

Cardinals right fielder Jason Heyward hit a home run in the top of the ninth off Phillies closer Jonathan Papelbon for the final margin.

St. Louis missed out on what would have been its sixth series sweep of the season after dominating the Phillies in the two previous games, scoring 22 total runs while setting and tying a single-game season-high in hits with 16 apiece on Friday and Saturday.

"Whenever you have those kind of offensive productions, guys don't forget about that," Matheny said. "It's just a shame we couldn't have finished it off.

"You get a young guy in here and you kind of get a couple opportunities you need to capitalize on it, but it's tough to keep that kind of expectation going all the time."

NOTES: The Phillies are just 5-14 (.357) so far in June, the lowest win total in the majors this month (next White Sox & Tigers, six wins). ... Cardinals SS Jhonny Peralta entered the game ranked 7tseventh in the National League in batting (.312) and his 11 home runs make him the league leader at his position. ... Cardinals starting pitchers entered the game with 32 wins, second in the majors (Pirates, 33) with 44 quality starts, second to Pittsburgh's and San Diego's 45. The starters hold a collective 2.61 ERA, tops in the majors.