Jayson Werth scrambles after he is hit by a pitch in the fourth inning. The Nationals loaded the bases with nobody out in the inning but only managed to score one run. (Ricky Carioti/The Washington Post)

The night had been billed as an event, a showdown between Bryce Harper and Mike Trout, but all that had been scrubbed away by the eighth inning at Nationals Park. Baseball is not an event sport. It’s a sport that frustrates and challenges, that asks the kind of questions Matt Williams faced Monday night. The game is on the line with the bases loaded, and you have three left-handed relievers available with a lefty coming to bat, and it’s your most trusted setup reliever on the mound, wobbling: what do you do?

As a rally mounted and Tyler Clippard teetered, the Washington Nationals’ bullpen remained dormant and Williams kept the faith. So take your pick whether Williams’s inaction or Clippard’s ineffectiveness — or some combination of both — led to the Nationals’ 4-2, gut-punch loss Monday night to the Los Angeles Angels.

The Nationals took a 1-0 lead into the eighth inning, carried by Tanner Roark’s 62 / 3 scoreless innings and Drew Storen’s clutch sequence against Trout, the player taken 15 spots after the Nationals selected Storen in the 2009 draft. Clippard allowed four runs, all of them unearned after Ian Desmond added to his league-high error total, as Williams let him face left-handed pinch-hitter Raul Ibanez with the bases loaded despite an arsenal of lefties at his disposal.

“Clip’s been the eighth-inning guy here for a long time,” Williams said. “Certainly, track record indicates that he’s good against lefties. He’s just as effective against left-handers as he is right-handers. So I want to stay with him there. I want him to be our guy that shuts down that eighth inning. Tonight wasn’t his night, though.”

Before the decisive eighth, the meandering, compelling game had been dictated mostly by the players not named Harper (who finished 0 for 3 with a walk) and Trout (2 for 5). The Nationals took advantage of Garrett Richards’s stunning spasm of wildness for their only run, which came in the fourth.

Williams handed the lead to Clippard, who for the past four years has been the most durable, and one of the most reliable, setup relievers in baseball. “He’s the best in the business,” Williams said. This season, though, he has faltered. He failed again Monday after another steady contributor in a recent slump betrayed him.

Clippard started the eighth by inducing a slow roller up the middle from Albert Pujols. Desmond, a Gold Glove finalist the past two seasons, ranged to his left and booted it, his league-high eighth error.

“A difficult error,” Williams said. “He’s got to range way to the middle.”

How difficult?

“I’m a big-league shortstop,” Desmond said. “Not that tough.”

Clippard allowed Pujols a stealth steal of second as he struck out Ian Stewart. Howie Kendrick reached on an infield single to Desmond, who nearly deked Pujols at third base. Brennan Boesch popped out, bringing Clippard one out from escape.

He couldn’t. Erick Aybar lashed a fastball through the right side, which scored the tying run and kept two runners on base.

“Probably wasn’t the right pitch selection,” Clippard said. “But I pulled it right down the middle, and he got a base hit. I had numerous opportunities to get out of that inning. It didn’t happen.”

As Clippard pitched to Chris Iannetta, the bullpen didn’t stir. Clippard walked him to load the bases — “the biggest thing that hurt me,” Clippard said.

Angels Manager Mike Scioscia summoned the 41-year-old Ibanez, who had torched the Nationals his entire career, particularly Clippard. Ibanez had smacked three hits, including two homers, off Clippard in nine at-bats.

Williams had three available left-handed relievers, two of which had nominal history against Ibanez. He had gone 3 for 10 against Jerry Blevins and 2 for 11 against Ross Detwiler. Xavier Cedeno was just up from Class AAA Syracuse. Williams stuck with Clippard.

“We have our guys set in the bullpen the way we want to have them set,” Williams said. “I think that the fact that he just hasn’t had location is worrisome on his mind, but I also want him to close down eighth innings for us.”

Clippard started Ibanez with a change-up, his best pitch, low and away, and Ibanez swung over it. “He’s a guy that traditionally hunts fastballs, and I knew that,” Clippard said.

He tried the same pitch again, and Ibanez drilled it to the left-center field gap. The bases cleared, and for good measure, Desmond’s throw sailed wide and allowed Ibanez to scoot to third, giving the shortstop nine errors in 20 games.

Both Clippard and Williams agreed Ibanez had hit a good pitch. The confident swing Ibanez took made Clippard consider reviewing film to see if he had tipped the pitch.

“It’s just something when a guy takes a swing like that on a pitch that you think is a good pitch — I looked at the video, it was a pretty good pitch — and he put a really good swing on it,” Clippard said. “It just makes you wonder. But at the end of the day these guys get paid, too.”

Finally, Williams pulled Clippard from his latest debacle. In 11 appearances, Clippard has blown two leads and let three ties turn into deficits.

Clippard still felt confident his change-up has induced poor swings. Monday night, two hitters reached base on balls that didn’t leave the infield, and he believed he had thrown a good pitch that blew the game. Still, he knows, something must change.

“Things just have snowballed on me a little bit here,” Clippard said. “I’ve [been] going through a rough patch. This month hasn’t been very good to me. But it’s up to me to get out of it. I can sit here and make all the excuses in the world and say I’m doing this right or this wrong or whatever it is, but at the end of the day what matters is the results, and the results haven’t been there so far this year for me. And nobody’s going to feel sorry for me so I just got to get out of it and do what I know how to do.”