"You're seeing his confidence getting higher and higher," Rizzo said. "His stuff is unbelievable."
The Cubs have won seven straight and earned their 10th series sweep of the season, surpassing last year's total.
Hendricks, who owns the second-best ERA in the Majors behind only the injured Clayton Kershaw's 1.79, allowed three earned runs or fewer for a 15th consecutive start.
"I got away from my long-toss program last year, and I went back to it this year," Hendricks said. "It's helped me a lot. I feel a lot stronger."
Hendricks has a lot of other things going for him, particularly from the mental side. In addition to his rising confidence, Hendricks tries to keep "simple thoughts and to make good pitches." For the most part, he's hitting his spots and when he does miss, it's not by much.
"There's nothing over the plate," he said. "My changeup was really good, my command of it. I was using my curveball well in spots. I didn't use it a lot but picked good spots to use it, or Willie [Contreras] picked good spots to use it. When you're rolling like this, you try to stay in that same mindset, keep doing your same work, notice what you need for what team you're facing and work on that in your bullpen."
Hendricks said no one was worried when things weren't going as well before the All-Star break. The Cubs have almost doubled their lead in the NL Central since just before the break.
"We knew we were just in a long stretch there before the break," Hendricks said. "We knew we just needed to get a little breather, get a few days under our belt. We knew guys would get their legs back under them and we'd start feeling better. Definitely no panic, but we wanted obviously to play well and establish something out of the break."
• Cubs manager Joe Maddon said he's trying not to overuse young reliever Carl Edwards Jr., despite the temptation. Edwards has allowed three runs in 18 innings with 25 strikeouts and five walks.
"He's been nothing short of outstanding," Maddon said. "We want to be careful with him. Could he start? I have no opinion on that. I don't want him to hit the wall. He's pretty much a bullpen guy to me. He can be something special."