That he was, giving up his only run on Alex Gordon's leadoff homer in the first inning, and then settling into an outing reminiscent of many he had on the same field as a Royal.
"It was exciting. It wasn't any more [exciting] getting ready for the game or anything, but probably it started earlier. When I woke up, I was probably a little more excited than usual," Greinke said. "Once I got to the park, it was the same. And once I was on the mound it was the same, too."
It was Gordon, too, who scored the game-winning run in the eighth after opening that inning with a double off reliever Francisco Rodriguez. The ball sailed over left fielder Ryan Braun.
"I knew it had a chance to get over his head," Gordon said.
Chris Getz bunted Gordon to third and Billy Butler lined a single into center field to get him home. So it was Gordon from start to finish.
Gordon said "Welcome back, Zack" immediately with a soaring drive over the right-center field wall and into the fountains.
"He threw me all heaters and I heard kind of grunting so I think he was coming after me a little bit and wanted to get off on a good start," Gordon said. "He threw me a couple good close pitches, but I was able to get one up. I hadn't hit a home run for a while so I didn't know how to do it."
Splish, splash and with a 431-foot blast it was Royals 1, Greinke 0.
"I pitched him really good, and I got to 3-2. He was leading off the game, so I was making sure to throw a strike. I didn't want to walk the leadoff guy," Greinke said. "I let him hit it, and he hit it pretty good. I do it all the time, just worked out for them that time. It was right down the middle. It was one of those things. To lead off the game you don't want to walk the leadoff guy."
It was just the third home run off Greinke this season and something of a rarity for Gordon, too. It was his fifth of the year, but his first to leave the park after 150 consecutive at-bats.
But this was familiar ground for Greinke -- he'd made 88 starts and pitched in 108 games at Kauffman for the Royals -- and he quickly settled in with strikeouts of Getz and Butler.
But Mendoza was stealing his thunder. Here he was, the stand-in starter for injured Felipe Paulino, and he was working relentlessly on a no-hit game.
"Every inning, I was like, 'OK, no hits in this inning,' " Mendoza said. "Of course I knew I was throwing a no-hitter, but I just wanted to do a good job and win the game."
There was a quick end to the no-hitter as the seventh began. Braun hit a sharp-hop grounder down the line that third baseman Mike Moustakas grabbed while trying to keep his footing in foul ground. Braun beat the throw and the ball sailed past first baseman Eric Hosmer. Second baseman Getz, backing up, recovered, but his throw went awry and Braun reached third. Braun got a single; Moustakas and Getz each got an error.
"He got through the sixth inning with no hits and you could start sniffin' it," Yost said. "You never know what could've happened if Moose hadn't slipped on Braun's ball because I think he'd have thrown him out."
When Mendoza walked the next batter, Ramirez, manager Ned Yost turned to reliever Aaron Crow. His no-hit shot gone, but much appreciated, Mendoza exited to a standing ovation.
The crowd was quickly on its feet again as Taylor Green flied out to Gordon next to the left-field line. Braun tagged up and fled, but Gordon's throw beat him and catcher Humberto Quintero, with an artful turn, tagged Braun for a double play.
"I kind of knew they were going to send him because the angle was kind of tough so I just tried to keep it to the right side of him and snuck it by him and Quintero made a great play," Gordon said.
Not everything went so perfectly in the inning for the Royals, though, because Rickie Weeks' looper off Crow dropped safely in left-center field and Ramirez scored for a 1-1 tie.
But then came Butler's eighth-inning RBI single.
"It felt good to get us the lead and get [Jonathan] Broxton in there," Butler said.
Broxton, though, kept everyone on high alert before nailing down his 15th save. Ramirez led off with a single and, after an out, Weeks' grounder up the middle was cut off by Getz behind second base. His throw to first base was late and in the dirt, but Hosmer kept the ball from getting away, saving a run.
"It was a great play for Getzy to get there, wheel and throw and then for Hoz to stop the ball," Yost said.
Broxton struck out pinch-hitter George Kottaras and retired pinch-hitter Brooks Conrad on a sharp grounder up the middle that shortstop Alcides Escobar fielded. Whew!
"Some of them are interesting and some of them aren't," Broxton said.
Are they ever.