WASHINGTON -- Starting pitching has been the Giants’ strength all season, as the rotation entered Sunday with a 3.02 ERA -- third best in MLB. However, from the first batter onward in the series finale in Washington, this team did not look like its National League-leading self, taking a 5-0 loss at Nationals Park.

In the first inning of Sunday’s contest, Johnny Cueto allowed a leadoff homer to Kyle Schwarber, in the pair’s first meeting since 2018. Three batters later, third baseman Wilmer Flores committed a fielding error, allowing Ryan Zimmerman to reach base with two outs. Cueto would need to toss seven more pitches to end the inning, his team down by one run.

In the bottom of the second inning, it was Cueto who committed a fielding error, allowing Victor Robles to reach first base and Alex Avila to advance to second on a sac bunt by Joe Ross, the first of three on the day for the Nats starter. This teed up Schwarber to smack a three-run shot, his second homer of the game.

The two errors are tied for the most allowed this season by the Giants. Entering Sunday, they had committed the second-fewest errors (25) in MLB.

Cueto allowed a season-high nine hits over 5 1/3 innings. The Giants’ bullpen was taxed, using seven pitchers in Game 2 of Saturday’s doubleheader, so manager Gabe Kapler stuck with Cueto as long as he could.

“Johnny was pretty gutsy and giving us the length that we needed to kind of get to [José] Álvarez, who bridged to [Jimmie] Sherfy,” said Kapler. “Those are the small wins within a game that really keep you afloat going into a new series. A lot of appreciation for Johnny's toughness and willingness to keep going back out there for us.”

The Giants could not catch a break on Sunday, nor could they jump-start their offense. Between the uncharacteristic errors, the lack of fresh arms in the bullpen and the Nationals’ defense, San Francisco split the series with Washington, having scored just three runs on 17 hits over four games. The Giants were shut out twice.

“This entire series hasn't been our best offensive performance,” said Kapler. “We have a better brand of offense in us, and I think we've seen that at various points through the season. I think we can be more selective, and at times, more aggressive. I also think that we have an even higher level of competitiveness in us.”

In the top of the sixth inning, the Giants’ rally was cut by two athletic plays by the Nats. Mike Tauchman smacked a 400-foot ball that looked an awful lot like a home run -- that is, until Robles made a leaping catch against the wall. The Giants challenged the call and won -- no catch, as it ricocheted off the wall before landing in Robles’ glove -- and Tauchman was awarded a double. However, two batters later, Juan Soto dove and caught what looked like an RBI single from Buster Posey, ending the inning.

“There's a lot of randomness in this sport, as we all know,” said Kapler, when asked what the offense can do to turn things around. “I don't think there's one thing to point to at this point. I think we're going to dig a little bit. Peel back some layers and see what we come up with. I just don't necessarily know that I have anything specific right now.”

The Giants’ three runs over the four-game series in Washington are the fewest they’ve scored in a four-plus-game set since March 29- April 1, 2018, against the Dodgers in Los Angeles. San Francisco put up just two runs in that series.

“The more you let it linger, the more you get frustrated and the more you try and do too much,” said Mike Yastrzemski. “We can't win this game anymore. It's over, so we can't go back and do anything. So we just look to the next one and try and be as good, precise and disciplined as we can. Just play our game and trust that it's going to be there.”