On Sunday afternoon, preparing for his start out in the visiting bullpen at Petco Park, Jordan Zimmermann felt terrible. His curveballs were flat. His fastball strayed from the target. Washington Nationals pitching coach Steve McCatty thought he lacked focus. Zimmermann realized first pitch was five minutes later than he thought. “It was really bad,” catcher Jose Lobaton said.

As Zimmermann walked through the gate, bullpen catcher Nilson Robledo sidled next to McCatty. Robledo plays catch with Washington Nationals starters daily, and he sometimes can sense what others cannot.

“He’s on today,” Robledo said to McCatty.

“How do you know?” McCatty asked.

“He’s on,” Robledo replied.

Once Zimmermann climbed the mound, his bullpen troubles ceded to nine masterful innings in a 6-0 victory over the punchless San Diego Padres. In one of the best starts in the Nationals’ brief history, Zimmermann struck out 12, walked none and retired the first 16 batters he faced. Eighty-three of his 114 pitches were strikes, and only once did he move to a three-ball count. He baffled hitters, induced helplessly ugly swings and convinced himself he should feel terrible before every start.

“I guess that’s the way it works,” Zimmermann said. “When that’s bad, it’s usually a good game.”

Good? Even if it came against an offense that just hit .135 over a six-game homestand, it ranked among the best starts ever by a National. Only John Patterson, back in 2005, had struck out at least 12 and walked none in a complete game.

On that day, Patterson yielded four hits. The only base runners Zimmermann allowed came when Alexi Amarista flared a single to right in the sixth and Seth Smith hit a triple to right, a ball Jayson Werth could have caught and certainly should have kept in front of him.