ST. LOUIS -- After three straight shaky starts, there was a sense that St. Louis Cardinals starter Lance Lynn was pitching for his spot in the team's postseason rotation Wednesday night.

If that was the case, Lynn made a convincing case for his inclusion.

Checking the Cincinnati Reds on three hits over six scoreless innings, Lynn won for the first time since Aug. 29 as St. Louis polished off its third Busch Stadium sweep of them in the last two years with a 10-2 rout.

In upping his mark to 12-10, Lynn walked none and fanned four, retiring 10 of the first 11 men he faced and then knocking down the last seven after yielding consecutive one-out singles in the fourth.

"Today was a very good representation of how he should go about his business," Cardinals manager Mike Matheny said of Lynn. "He controlled his fastball from the top to the bottom of the zone."

Matheny said Lynn, coming off an outing Friday in which he issued six walks in 3 1/3 innings at the Chicago Cubs, made an adjustment that helped him stay through the ball. Lynn coyly refused to confirm any talk of adjustments, simply saying that it was just a matter of commanding his fastball.

"I wasn't worried about anything," Lynn said.

In his prior three outings, Lynn was roughed up for 15 hits and 12 runs over 11 2/3 innings, walking 11 and whiffing seven. Given his combined 0-5 record against Pittsburgh and Chicago -- St. Louis at present will play one of them in the National League Division Series -- Lynn remains a candidate to be bypassed from the team's rotation.

But Matheny cautioned against making any assumptions that Lynn is bullpen-bound for the first round.

"It's the elephant in the room; everyone knows about it," Matheny said of the team's playoff rotation. "But it doesn't detract from our philsophy of taking it one game at a time. We've got a lot of baseball to play."

Particularly if the Cardinals continue to hit as they did in this one. With second baseman Matt Carpenter cracking two-run homers in the third and fifth inning, St. Louis belted four for the first time since July 11, 2014.

Right fielder Randal Grichuk and center fielder Peter Bourjos also clouted solo shots that traveled 420 feet or more, while third baseman Mark Reynolds doubled twice and knocked in a pair of runs.

Left fielder Matt Holliday started for the first time since July 29, when he injured his right quad for the second time this year, and rifled an RBI double off the right-center field wall to cap a three-run third inning.

Victimized by the Cardinals' first 10-run outburst since Aug. 23 in San Diego was Brandon Finnegan (4-1), who was touched for seven hits and six runs over five innings, walking one and fanning seven.

"It was one of those days where you make good pitches and you get put down," said Finnegan, who was acquired from Kansas City in the Johnny Cueto trade July 26. "I thought for the most part my stuff was good. They're a really good hitting team and they showed it tonight."

While St. Louis (96-56) reduced its magic number for clinching its third straight NL Central title to seven, Cincinnati (63-88) fell into the division cellar.

First baseman Joey Votto clubbed his 29th homer in the seventh for the Reds, but by that time, it was already 9-0 and the Cardinals were flooding the field with a plethora of September callups while Lynn was chilling out following a successful outing.

"I used it as fuel to get better," Lynn said of his recent struggles.

NOTES: St. Louis RHP Adam Wainwright (left Achilles) threw a 25-pitch simulated game Wednesday, working against teammates Matt Holliday, Matt Adams, Randal Grichuk and Pete Kozma. Wainwright is scheduled to throw again Friday or Saturday and could pitch in a game next week. ... When Cincinnati RHP Josh Smith starts Thursday night against the New York Mets, it will mark the 100th game that a rookie has started for the Reds this year. ... Cardinals LF Matt Holliday started for the first time since being activated from the 15-day DL on Sept. 15. He has gone on the DL twice this year with a right quad injury.