SAN FRANCISCO -- Every year, when the A's and Giants face off in the Bay Bridge Series, there's a unique energy in the ballpark as green and orange jerseys mingle in the crowd and loud cheers for both teams fill the air.

For the many young A's players experiencing the atmosphere for the first time, it was something special to behold.

"It was a fun game," left-hander Ken Waldichuk said. "I mean, it was a big crowd. They brought a lot of energy. I definitely was able to kind of feel that. I feel like I almost kind of fed off it."

If Waldichuk was a little extra fired up, it certainly showed as he dealt in front of a sellout crowd Tuesday night at Oracle Park that saw two rival fanbases come together in protest of the A's plan to relocate to Las Vegas. Oakland fell, 2-1, in the opener of the two-game Bay Bridge Series, ultimately getting outdueled by San Francisco's pitching staff.

Waldichuk looked sharper than he has in a while, following opener Tayler Scott's scoreless first inning with 4 2/3 frames of one-run ball. Waldichuk struck out six while holding the Giants to one hit and two walks.

"You could see there was a little more energy, a little more emotion, when he threw the ball," manager Mark Kotsay said. "Probably the hardest he's thrown it all year."

Waldichuk retired his first nine batters in order, not permitting a baserunner until he issued a free pass to Wilmer Flores to lead off the fifth inning. That walk came around to haunt him, as he proceeded to load the bases with nobody out by giving up a base hit to Patrick Bailey and making a throwing error attempting to erase the lead runner while fielding Brett Wisely's bunt.

Flores went on to cross the plate on Casey Schmitt's sacrifice fly, which was bookended by a pair of strikeouts as Waldichuk managed to get out of the inning.

While it wasn't the outcome he wanted, he was able to take some solace in the fact that he was able to limit the damage to one unearned run.

"I think that's the way I have to think of it," Waldichuk said. "In the moment, I was kind of mad that I threw that ball away and I walked the leadoff guy."

The 25-year-old left-hander has struggled with consistency in his first full season in the big leagues, but he has shown some encouraging signs. Waldichuk's move to the bullpen in mid-May has not led to improved results thus far, but it allowed him to rethink his mindset.

When Waldichuk shifted back into the rotation to start the A's second-half opener, he said pitching in relief allowed him to loosen up and not over-prepare for his opponents. Instead, he went back to focusing on what he knows he does best.

That approach was evident on Tuesday night, as Waldichuk came out firing against the Giants. He touched 97 mph with his four-seamer in the second inning and averaged 95.2 mph on the offering, seeing an overall uptick in velocity among his three-pitch mix.

"It's definitely something we've talked about, trying to take it one inning at a time," Waldichuk said. "Being high-effort, rather than kind of pacing myself and waiting for something to happen first to empty the tank."

It's been nearly a year since Waldichuk came over to the A's organization as the top prospect in the deal that sent Frankie Montas to the Yankees at the Trade Deadline, and his big league experience amounts to 31 games (21 starts).

Waldichuk is still finding his footing in the Majors, and his team can see that effort in action -- even if he hasn't quite been able to reap the rewards thus far.

"I think Ken's realized when he comes into games now that max effort from pitch one is important," Kotsay said. "This is a sign of growth. It's a sign of maturity in terms of understanding what it takes to get Major League hitters out from pitch one."