SAN DIEGO -- With a large contingent of Cardinals fans roaring its approval, Adam Wainwright briefly thought he was in St. Louis.
"That was awesome," Wainwright said of the cheers that greeted him behind the Cardinals' dugout when he departed the game in the eighth inning. "Great fan support on the road. That was pretty special. It's not rare for our fans to show up, but it's rare for our fans to be louder than the home fans. It definitely felt like a home game."
Wainwright and the Cardinals made themselves at home at Petco Park, where they rolled to a 10-2 rout of the San Diego Padres before 18,702 fans Tuesday night.
Daniel Descalso hit his first grand slam and drove in a career-high five runs, but Wainwright set the tone, giving up a run on four hits with six strikeouts and a walk in his first win at Petco.
"I thought that was one of his better games," St. Louis manager Mike Matheny said. "Without question, the best change-up I've seen him throw. That definitely kept the left-hand hitters off balance. He had everything else working right. It was an impressive outing."
Wainwright (6-3) gave up a run in the second, but blanked the Padres from that point on. After a single by Chris Denorfia with no outs in the second, Wainwright retired 15 of the next 16 batters he faced, a single in the fifth to Alexi Amarista being the lone runner to reach base. He won for the first time at Petco, where he previously had a 0-2 mark with a 2.57 ERA. Citi Field in New York is the only National League park in which Wainwright hasn't registered a win.
"Wainwright was just a little too much for us," Padres manager Bud Black said. "We couldn't really solve Wainwright. Wasn't really commanding the ball the first couple of innings, then (he) took off."
Descalso, who went 3-for-3 with a walk after entering the game with a .197 batting average, drove a 1-2 off-speed pitch by reliever Anthony Bass over the right-field wall in the eighth after Black ordered an intentional walk to Jon Jay to load the bases with one out. It capped the Cardinals' blowout after a four-run fifth gave them a 5-1 cushion.
"It was a slider that covered a lot of the plate," Descalso said.
San Diego starter Edinson Volquez retired the first six batters he faced, but gave up a run in the third and fell apart in the fifth.
Volquez (3-5) allowed five runs on eight hits, six of those coming in the fifth, with five strikeouts and a walk in six innings. It was the second straight setback for Volquez after he had won his previous three starts.
"His first three innings, he pitched extremely well," Black said. "First-pitch strikes, ahead in the count. Good ball-strike ratio. They just strung some hits together in the (fifth inning)."
Jedd Gyorko helped the Padres (21-24) get on the board first. Gyorko led off the second by lifting a fly ball to center, which initially appeared to be a routine catch for Jay. But the Cardinals center fielder lost the ball in the twilight, allowing it to drop for a double. Gyorko advanced to third on a single to right by Denorfia before scoring when Amarista grounded into a double play for a 1-0 San Diego lead.
The Cardinals tied it in the third as Descalso scored on a double to center by Matt Carpenter that got past Amarista with two outs.
In St. Louis' fifth-inning uprising, Descalso doubled home Jay with no outs before Carlos Beltran drove in Descalso and Pete Kozma for a 4-1 advantage. A ground-rule double to right by Allen Craig scored Beltran to make it 5-1.
"I just think they made an adjustment," San Diego catcher John Baker said. "You're talking about a good hitting team over there. A perennial playoff team with some clutch players."
NOTES: Cardinals 3B David Freese missed his second straight game with an injured right thumb that required stitches. Freese injured the thumb Sundaywhen he got spiked tagging out Milwaukee's Norichika Aoki in a rundown. He could return to the lineup Wednesday. ... San Diego LF Carlos Quentin was held out of the lineup Tuesday after tweaking his right knee with an awkward slide at home in Monday's win over St. Louis. Quentin, who is hitting only .178 with four home runs and 14 RBI, is expected to return to the lineup Wednesday. ... St. Louis RHP Eduardo Sanchez was claimed off waivers Tuesday by the Cubs.