After struggling to a 6.14 ERA in four starts in April, Wellemeyer celebrated the calendar flip in style on Friday night, allowing just two runs on six hits over seven strong innings to lead the Cards to a 6-2 win over the host Nationals.
May heroics are nothing new for Wellemeyer (2-2), who was the National League Pitcher of the Month for May in 2008, when he went 4-0 with a 2.19 ERA in six starts in his first full season with St. Louis.
Don't think the 30-year-old veteran wasn't aware of that fact, either.
"Oh yeah, I thought about it, absolutely," Wellemeyer said. "April has not historically been very good to me. And May last year was excellent to me, so I just want to keep that going."
Wellemeyer got plenty of help from his teammates, who began the new month the way they spent most of April -- winning.
After enjoying the best April winning percentage in club history with a Major League-best 16-7 record to open the season, the Cards recovered from a sloppy 9-4 win on Thursday night with slick defense and timely power hitting in their Friday gem.
All six of the club's runs on the night came via the long ball, with most of the damage being inflicted by the middle of the order.
As so often has been the case, it was the reigning NL Player of the Week, Albert Pujols, leading the way early and often.
For the second night in a row, Pujols homered in the first inning, blasting a two-out solo shot to left field, his ninth of the season off of impressive Washington rookie Jordan Zimmermann (2-1) to give St. Louis a 1-0 lead.
Pujols ignited the next rally for the Cards (17-7) as well, leading off the fourth with a double to the wall. Chris Duncan followed by hitting his third home run of the season to make it 3-0 and give Wellemeyer a little breathing room, especially with Zimmermann looking good on his end.
"Their guy wasn't giving up much," admitted Cardinals manager Tony La Russa. "So it was important that [Wellemeyer] put zeroes on the board."
The Cards continued to use the power play to drive in their runs in the sixth, when Pujols singled to lead things off and scored on Ryan Ludwick's one-out blast onto the center-field berm, making it 5-0.
Pujols finished the night 3-for-4, a triple shy of the cycle, but he admitted it might have taken a little bit to achieve that particular feat on this night.
"I think I'm one of the slower guys on the team," said Pujols, who's hitting .356 this season but has yet to record a triple. "For me to get a triple, I think I'd need the outfielders to crash into the fences and maybe then I could get to third base."
And just so you don't think it was the usual power-hitting suspects doing all the offensive damage, rookie Joe Thurston capped the St. Louis scoring with his first big league homer, a line-drive solo shot into the home bullpen in right field in the seventh.
Thurston, 29, has 154 big league service days to his credit, but since most of it has come in September stints dating back to his 2002 Major League debut with the Los Angeles Dodgers, he still qualifies as a rookie since the requisite 45 days must come before Sept. 1 of a given year.
Sharing the third-base job with fellow "veteran rookie" Brian Barden, Thurston was hitting .278 in 54 at-bats with the Cards this season. Combined with his 66 big-league at-bats coming into the season and his 0-for-3 start to the night, his shining moment came in his 124th Major League at-bat.
"It felt really good," said Thurston, who in his third at-bat of the night had flown out to the deepest part of right field. "My third at-bat, I hit the ball well, but just too high. I don't have 'high pop' like some of our guys, but it got me feeling a little better going into that fourth at-bat."
The ball was retrieved from the bullpen for Thurston, who said someone had it tucked away "somewhere safe" for him.
And Thurston admitted, somewhat sheepishly, that yes, he knew it was gone as soon as he hit the offering from Nationals reliever Logan Kensing.
"Yes, I knew I got it good," Thurston said after a brief hesitation. "But I always run hard. I don't hit enough to jog around the bases."
The Nationals (5-17), who sport the worst record in the Majors right now, finally got on the board in the seventh, when Willie Harris connected for his first home run of the year, a two-run shot off Wellemeyer.
Lisa Winston is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.