The red-hot Royals, winners of seven of eight entering Friday, rolled into Milwaukee and seemed ready early to extend that success, grabbing a four-run lead through four innings.

But left-hander Danny Duffy, making his first start since he was skipped Tuesday for missing the team’s charter flight out of Kansas City on Monday, coughed up the lead by allowing six runs in the fourth inning.

The Brewers went on to win, 9-5.

• Box score

After the game, Duffy, speaking for the first time since Monday’s incident, confirmed that he indeed had a flat tire causing him to miss the team flight. Right-hander Jakob Junis took Duffy’s spot in the rotation Tuesday but allowed seven hits and five runs over 2 1/3 innings in an emergency start.

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“Missing a flight can’t happen,” Duffy said. “I felt like I let the team down. Jakob Junis has become one of my best friends, and I felt like I put him in a spot. He is an ultimate competitor. I didn’t give him much of an opportunity. ... I put our bullpen in a bad spot. It’s something that will never happen again. I regret that.

“I hit a pothole and blew out my right tire. My buddy came and got me and took me to the airport. It was a really, really bad day.”

Duffy, who added that he also mistook the time of the charter flight, took a separate flight Monday night to Milwaukee and addressed the team Tuesday.

“Everyone on the team,” he said, “every single one to a man, said, ‘We got you. We’ll pick you up.’”

Here are three ups and three downs from Friday’s game.

UP

Salvy stays hot
Royals catcher Salvador Perez has been ridiculously hot since returning from the disabled list a week ago. Perez had four more hits -- including his seventh home run -- and four RBIs on Friday. He even had a stolen base and now has a career-high six consecutive multi-hit games. Perez had a two-run double in the first, his sixth straight game with an extra-base hit. The club record is eight, set by Danny Tartabull in 1991. Perez is 15-for-26 during this stretch with five doubles and 10 RBIs.

Heads-up play by Mondesi
Royals shortstop Adalberto Mondesi, who leads the Majors in stolen bases with 18, has made several great baserunning plays this season, and he alertly made another in the third inning that got a run home. Mondesi led off with a hard single to right, and when right fielder Ryan Braun’s throw skipped into second baseman Keston Hiura near the outfield grass, Mondesi noticed no one was covering the bag. He made it to second easily, while Braun was charged with a throwing error. Mondesi then scored on a single by Perez.

Blewett makes debut
Royals right-hander Scott Blewett, a second-round Draft pick in 2014, made his MLB debut in the sixth. Blewett, 24, pitched two scoreless innings. He worked out of a two-on, two-out jam in the sixth by striking out Hiura. Blewett also stranded a runner on second in the seventh.

DOWN

Duffy’s struggles
Duffy looked extremely sharp for three innings, allowing just two singles and facing just 10 batters. He struck out four, including the side in the second inning.

But Duffy completely lost his command in the fourth. Christian Yelich led off the frame with an opposite-field homer on a 2-0 fastball. Two walks and two singles sandwiched around a fly out forced in another run. After Duffy got the second out on a strikeout, catcher Jacob Nottingham, who looked overmatched when striking out on a fastball in the third, got a first-pitch slider from Duffy and blasted it to left field for a grand slam.

Duffy said he didn’t regret throwing Nottingham the slider.

“It was supposed to be down and in,” Duffy said. “It was just kind of a cement-mixer that unfortunately stayed up middle and in. I don’t typically look in hindsight at pitches I’d wish I’d thrown. I just wish I’d executed better.”

Added Royals manager Mike Matheny, “He walked through the third inning on eight pitches, and then he just hit a wall. Unfortunately, he got into a spot at the bottom of the order with an opportunity to get one big out, but that first-pitch breaking ball hurt him.”

Nottingham’s approach?

“You're just trying to fight right there,” he said. “With two outs, you're just trying to get somebody across the board just to get something going. So to be able to barrel that ball up and have it go over was awesome.”

Duffy was out after 3 2/3 innings, having allowed seven hits and six runs.

Missed chance
Already up 4-0 in the third, the Royals looked primed to add on after Perez’s RBI single to score Mondesi with none out. Perez stole second, but Maikel Franco hit a dribbler in front of the plate and Perez was easily thrown out trying to advance to third. Hunter Dozier then flied out and Alex Gordon popped out -- on a 3-0 pitch -- and the threat vanished.

Another missed chance
Down 9-4 in the sixth, the Royals had a great chance to crawl back in the game. Gordon singled to left and Ryan O'Hearn doubled down the left-field line. The Brewers played their infield back, conceding a run with none out. But Edward Olivares popped out to short center field, Nicky Lopez struck out swinging and Whit Merrifield grounded out.

“Jumping out [to a 4-0] lead, we haven’t thrown those away often this year,” Matheny said. “We had chances to keep pecking away when they had nine on the board. We had a chance to get some momentum going.”