"You look at the numbers, and they're outstanding again," Maddon said of Arrieta, who has a 2.55 ERA. "You become more hyper-critical after a guy's achieved what he did last year, and what he achieved last year and how he did it is almost impossible to replicate. That was wire-to-wire incredible."
Arrieta struck out six and scattered four hits on Friday, but what Maddon liked was how the right-hander looked.
"The fastball had extra life at the end, the strike-throwing was better, the curveball had great depth," Maddon said. "That reminded me of last year, physically."
Is Arrieta competing with his second-half self?
"I think I'm competing with [Kyle] Hendricks now," Arrieta quipped.
Hendricks, the Cubs' fifth starter who will be on the mound Saturday, ranks second in the Major Leagues with a 2.17 ERA. Arrieta ranks fifth with a 2.55 ERA.
"There's certain things I look back on last year and try to replicate for the benefit of our ballclub and try to carry it over for future outings," Arrieta said. "I think there's a lot of room to improve on all the way around, and that's what I try to do between starts."
It wasn't a perfect outing. Arrieta did give up a solo homer to Stephen Piscotty in the fifth, the first off the ace at Wrigley since July 25, 2015. That snapped a streak of 15 consecutive home starts without giving up a homer, the longest by a Cubs starter since Bill Lee went 17 straight from 1942-47.
One player who doesn't want to face Arrieta again is the Cardinals' Matt Carpenter, who went 0-for-3, and now is 0-for-21 lifetime against his one-time TCU teammate.
"We like to compete against each other," Arrieta said. "It's a little different playing against [the Cardinals]. The rivalry we have, there's a lot of history there. It kind of adds to the competitiveness between the two of us. It's work between the lines, and fun outside of that. We'll continue to fight against each other and go from there."