Siegrist, though, was satisfied with the outcome in his sixth and likely final appearance -- he struck out eight over four innings -- and fellow Cardinals prospect Mike O'Neill hit a go-ahead RBI single in the eighth to send Surprise past Scottdale, 4-3, on Monday.
Siegrist set a season-high in strikeouts while throwing 45 of his 66 pitches for strikes.
"I felt really good," he said. "My fastball, everything was pretty much working. My slider, I thought I was throwing a little slower than usual, but other than that, I felt pretty good."
Siegrist, a lefty who went 7-2 with a 2.77 ERA in 18 games (17 starts) at two levels in 2012, said his strikeout-filled effort Monday wasn't the result of him emptying the tank in his last start.
"I approach every game the same," said Siegrist, who split the 2012 season between Class A Advanced Palm Beach and Double-A Springfield in the St. Louis system and struck out 68 in 87 2/3 innings. "I have a plan and I just happened to get more strikeouts than usual."
He couldn't pitch his way past Panik's theft in the third, though. The Scottsdale shortstop hit a one-out single and advanced to third on David Adams' (Yankees) single to right. Siegrist made a pickoff throw to first and Panik took off, scoring without a throw.
Romine (Yankees) then took a called third strike at the knees and lost his cool.
"It was a changeup. I mean, it was pretty borderline, I guess it could have gone both ways," said Siegrist. "I didn't care if he got ejected."
Siegrist was in control the other three frames, though. He struck out the side in the first, worked around a single and a walk in the second and whiffed two more in the fourth after beaning Adalberto Santos (Pirates) to start the inning.
The Cardinals' 41st-round pick in 2008 said he came to Arizona with a goal of proving his worth and refining his secondary pitch.
"I wanted people to know that I could get the job done here, pretty much," he said. "I'm working on my slider, and everything felt good."
Siegrist, 23, hopes his stint in Arizona will be a good segue to Spring Training. In 19 innings this fall, the southpaw from Palm Beach Community College went 2-1 with a 2.37 ERA and 27 strikeouts. He'll be back in Palm Beach, Fla., in a few months before heading to either Springfield or Triple-A Memphis.
"It's helped a lot, just with the slider -- that's really what I've had to work on and I think it's pretty good," he said. "Hopefully I can build off that confidence."
Surprise took a lead in the second inning when Kellin Deglan (Rangers) hit his first homer, a two-run drive off Bobby Cassevah (Angels).
Gift Ngoepe (Pirates) added his first longball of the fall in the seventh, also a two-run shot, to bring Scottsdale to within a run. Mets right-hander Greg Peavey came on and fired a pair of scoreless frames, though, to close out Surprise's 16th win.