Gio Gonzalez hit town Thursday for what may be the first brilliant performance of a seven-year gig at Nationals Park. The grinning Gio, who has so much personality he can hardly contain it, brought all the answers to questions that have hovered over him for weeks. For the sellout crowd of 40,907, there were many memories in a 3-2, 10-inning win in the Washington Nationals’ home opener. But for long-term impact, Gonzalez’s importance stood alone.

Why did the Nats trade four prospects for this guy? Why did the team lock him up for five years for $42 million, plus two more seasons of team options? That’s a Franchise Cornerstone price. What’s so great about a lefty who gets boxed around in spring training, then knocked out in his first start?

Against the hard-hitting Reds, Gonzalez worked seven scoreless innings, allowed just two hits, walked nobody and fanned seven, including two overpowering whiffs of Joey Votto, who just received a $251 million contract extension. For 97 pitches, plus the first base hit of his pro career, as well as a fun and farcical tour of the bases, Gonzalez showed all the reasons why he should be a core piece of a dominant Washington rotation for years to come.

“Gio was filthy,” said Roger Bernadina, who had the perfect view from center field all afternoon. “You could see he’s an all-star pitcher. Not just the curveball but also the way he had the fastball [tailing] back over the outside corner to Votto. And he keeps the change-up low. He’s just nasty.”

As an added attraction, especially on a team with plenty of stoic starters who seldom show their emotions, Gonzalez simply couldn’t disguise his joy. He plays to please. When he got his unexpected hit, he laughed at first base. He ran around the bases without ever rounding any of them, simply planting his foot on second and third as if further adventure terrified him. And as he walked off the mound, he basked in a standing ovation. It’s impossible to read a crowd’s collective mind. But this one thought, “Oh, Lord, Stephen Strasburg, Jordan Zimmermann and this guy’s as good as advertised, too?”

All spring, Gonzalez has tried to stifle his personality because he wants to fit into his new team, not be thought a hot dog and, after this performance, he praised almost every teammate and a few hot dog vendors. But he just can’t be bland.

“The crowd showed a lot of love. What better than give it back,” he said. “I gave the fans what they wanted . . . And we won it [in the end] to put big smiles on everybody’s faces.”

This game, despite a crisp beautiful day, a walk-off win and a 5-2 record that puts the Nats in first place alone, will be forgotten. The importance of Gonzalez may last for many years.

“What we saw today, that’s the guy we traded for — with upside to be even better than that,” General Manager Mike Rizzo said. “If his walks get down to 3.5 [per nine innings], he’s elite.”

Gonzalez is working on it. He went to three balls just three times. “That’s what I wanted to do: prove a bunch of people wrong on that,” Gonzalez said about his past tendency toward 4.1 walks per nine innings.