Molina also cut down Rizzo when the big first baseman tried to steal third following his two-out RBI double in the first. But the Cardinals had their own baserunning blunder in the fifth, when Carpenter was thrown out after he made a wide turn at second on Beltran's run-scoring single.
Westbrook allowed four runs — three earned — and nine hits in 5 1-3 innings, increasing his ERA from 1.07 to 1.62. He had allowed just four earned runs all year.
"I was battling my location today," he said. "Kind of fighting pretty much all day."
Carlos Villanueva pitched 6 2-3 innings for Chicago and was charged with three runs and seven hits. He has a 3.02 ERA in seven starts, but only one victory.
"You can see the boys coming alive now. The weather is warming up a little bit. We're right there," Villanueva said. "We're close. Keep chipping away."
NOTES: Schierholtz made two nice catches in right. ... Cubs RHP Kevin Gregg has converted each of his five save opportunities since he was promoted from Triple-A Iowa on April 16, seizing the vacant closer role that's already been held this season by Carlos Marmol and injured RHP Kyuji Fujikawa. "Gregg's our closer. That's pretty much the way it is right now," manager Dale Sveum said. "He's obviously earned it. There's a bigger sample out there now to know that." ... Cubs 2B Darwin Barney and LF Alfonso Soriano got the day off. ... The Cardinals are off Thursday, then host the Rockies on Friday. RHP Shelby Miller (4-2, 1.96 ERA) faces Colorado RHP Jon Garland (2-2, 4.65) in the opener of the weekend series. ... Chicago begins a three-game series at Washington on Friday. RHP Jeff Samardzija (1-4, 3.09) is scheduled to face Washington LHP Ross Detwiler (1-3, 2.50).