"It's very ... I really can't believe it," Jacobson said. "The first time I started in pro ball was a month ago."
The reliever-turned-starter faced three batters over the minimum in the highlight of his five-year career as the Double-A New Britain Rock Cats blanked the Reading Phillies, 6-0.
Jacobson (3-0) struck out eight and issued one walk. His previous career high was five innings -- he lasted that long in each of his previous three starts.
"It's my lifetime high," he said with a laugh. "I was definitely getting a little tired, but I just put the ball over the plate and let my defense make plays."
The help arrived almost immediately. After allowing Freddy Galvis' leadoff single and Michael Spidale's one-out base hit, Jacobson struck out Matt Rizzotti and batterymate Chris Herrmann threw out Galvis trying to steal third.
Jacobson retired the next 11 Phillies until Steve Susdorf singled in the fifth. He said he benefited from multiple diving catches in the outfield and handiwork in the infield, too.
The 24-year-old right-hander relied almost exclusively on his fastball, only going to his slider and curveball in two-strike counts. He threw 95 pitches, another career high, and recovered from a ninth-inning walk to keep a reliever warming in the bullpen.
Jacobson, acquired by the Twins from the Orioles in last December's J.J. Hardy trade, formerly was the property of the Tigers. Detroit made him its fourth-round pick in the 2008 Draft out of Vanderbilt University, where he was a starter.
Jacobson's first 104 professional appearances, however, were all in relief. Then, on May 9 and May 14, he made a pair of starts, combining to allow two runs on four hits over seven innings.
"Early on in the season, I had some extended outings in the bullpen and we had a couple guys injured," Jacobson explained. "I was a good candidate to make a couple of spot starts. They asked; I said, 'Yeah, definitely.'"
Jacobson said he did not treat the opportunities as auditions. After four seasons of relieving, full-time starting wasn't on his mind. It was, however, on the minds of the Rock Cats coaching staff.
His fifth start since joining the rotation was clearly his best. He is 2-0 with a 1.54 ERA as a starter after going 1-0 with a 2.70 ERA in relief.
"Now I have figured out my personal routine and have a good feeling," Jacobson said. "It's great and it's getting better and better with every start."
Nate Hanson doubled home two runs in the fourth against Reading starter J.C. Ramirez (5-6). Daniel Rohlfing also plated a pair for New Britain.