PITTSBURGH — Go ahead, take your best shot. Try to nitpick a weakness worth addressing on the fastest-starting Cubs team in 109 years.

That’s what team president Theo Epstein and his front office are doing these days, even with the Cubs setting the pace in the majors with a 20-6 record and major-league leading totals in runs scored, fewest allowed, team ERA, walks drawn, disco-ball parties and zany dress-up days.

“I think we’ve played really well, and we’re happy with the record that we have,” Epstein said. “But I don’t think we’ve completely locked in yet, or clicked in all facets of the game.”

Jorge Soler’s slumping bat and clumsy fielding? Trevor Cahill’s recent struggles out of the bullpen? Pedro Strop’s strange fascination with the Teenage Mutant Ninja Turtles? There isn’t much — especially after the Cubs finished off a statement-worthy sweep of the playoff-minded Pirates with Wednesday’s 6-2 victory on the strength of home runs by Ben Zobrist and Anthony Rizzo.

“Our pitching staff’s really been carrying us, been the most consistent part of our team,” said Epstein, who retooled a 97-win team with a $290 million winter — and who keeps looking for more. “As it warms up here, I think the bats will get going, and they’ll probably carry us for a while.

“But as far as needs that we might have or ways that we can get better, we’re always assessing that, and there’s lots of different ways that we could potentially improve the club before the end of the season.”

No need to push Heyward:

A monthlong issue with a sore right wrist kept right-fielder Jason Heyward sidelined for a third consecutive game Wednesday, but the Cubs aren’t considering the disabled list.

“That’s still my impression,” said manager Joe Maddon, who had second baseman Zobrist make his first outfield start of the season, in right. “We’ve been going fine, played a couple of nice games here. No reason to push it.”

Maddon said after the game Heyward had made “good progress,” and that he planned to draw up two lineups for Thursday and then check on Heyward’s status before deciding which to use.

Sweep numbers:

A few hours before Wednesday’s game, as Maddon met with media in the dugout a stadium worker picked that moment to start sweeping the dugout, raising dust around the group.

Eventually, he was asked to stop. The Cubs took it from there.

Their three-game sweep of the division-rival Pirates that looked unlikely when the week started looked decisive by the time they were done outscoring the Pirates 20-5 over three days.

• The Cubs trailed the first two innings of the series (1-0 on Andrew McCutchen’s first-inning homer Monday) and not again for the remaining 25.

• They failed to reach base in only four of 27 innings.

• Pirates starters needed 300 innings to pitch a combined 14 innings, none of them lasting more than five. That included Juan Nicasio making it just 4? innings on Wednesday (102 pitches).

• Cubs starters, meanwhile, allowed just two runs in 17? innings, none during Jon Lester’s 5?-inning start Wednesday during which he pulled two Houdini acts to escape a bases-loaded, none-out jam in the fourth and a first-and-third, one-out threat in the fifth.

“We’ve done a good job so far,” said Lester, who was not willing to suggest an upper hand in the NL Central, despite the Cubs’ 13-2 division record — 5-1 against St. Louis and Pittsburgh.

“We know what we’re up against in this division,” he said. “That’s a good ballclub. The Cardinals are a good ballclub. And we know we have to go through those two teams to get where we want to go.”

• This report was produced in partnership with the Chicago Sun-Times. For related coverage, check chicago.suntimes.com.