AP photo by Adam Hunger / New York Yankees outfielder Clint Frazier watches his two-run home run against the host New York Mets during the fourth inning of an exhibition game Saturday night.

NEW YORK — Didi Gregorius watched over the top of his face mask as his drive off Washington Nationals ace Max Scherzer sailed into empty outfield seats.

Fake cheers — meant to encourage the hometown team — accidentally piped through the stadium as the Philadelphia Phillies shortstop rounded the bases. After touching home plate, he pantomimed air-fives to teammates.

"This is 2020 baseball," Scherzer said. "Embrace it and have fun with it."

Exhibition games in Washington, New York and Pittsburgh on Saturday gave Major League Baseball its first look at coronavirus-era games: cardboard cutouts of fans in place of live ones in the stands, sound effects for crowds, unprecedented marketing opportunities and more. Still, for clubs limited to practices and intrasquads in their own ballparks for the past two weeks, Saturday stood as an important milestone as MLB tries to start a shortened 60-game season Thursday during a pandemic.

"In some ways, this is very much a dress rehearsal for the new world we're in," New York Yankees manager Aaron Boone said before an exhibition hosted by the crosstown Mets.

No fans rushed off the 7 train in Flushing at Citi Field, and no masses hurried over the Clemente Bridge in Pittsburgh — not with MLB planning to start this pandemic-shaken season at empty stadiums. At Nationals Park, several people watched from a building balcony far beyond the left field wall.

Umpires wore face masks, as did some players. Backups watched from the stands to maintain social distancing in dugouts. They all tried to follow safety protocols, including a ban on licking fingers or spitting.

And in another new look, the Mets became the first club to sell ad space on the field itself, spray painting a Ford logo on the back of the pitcher's mound.

Gregorius drilled a three-run homer in the first inning in Washington, the first big fly by a player in any of Saturday's games.

The 30-year-old Phillies newcomer is one of a handful of players who has said he will wear a mask full-time this season. Gregorius has a chronic kidney disorder that puts him at high risk for the coronavirus.

Scherzer is expected to throw the first pitch of the regular season when the Nats, the reigning World Series champions, host new ace Gerrit Cole and the Yankees on Thursday night. The right-hander struggled in his final tuneup, also allowing a three-run shot to former teammate Bryce Harper.

Booed heartily last season after spurning Washington in free agency, Harper heard no such jeers this time.

For their first exhibition game since the virus outbreak shut down spring training in mid-March, the Yankees took a team bus from the Bronx to Queens to meet the Mets — no subways for this series.

The pregame routine looked familiar enough, though, with soaring batting practice homers from Giancarlo Stanton and Pete Alonso, ground ball work for Gleyber Torres and Robinson Canó.

Signs of the times were certainly there. Some coaches hit fungoes while wearing face masks, and the usual high fives and hugs between opponents around the batting cage were replaced by elbow taps and distanced chats — including one between Yankees general manager Brian Cashman and Mets counterpart Brodie Van Wagenen.

With no fans filing in for first pitch, nearly 1,000 cardboard likenesses of Mets supporters were set up behind home plate. The team plans to have 5,000 in place by opening day.

Reserve players watched from under large awnings built behind both dugouts. Mets backups gave a standing ovation to scheduled starter Rick Porcello as he returned from the bullpen, then started a chant of "Let's go, Mets!"

The first homer in Flushing also came from a masked player — Yankees outfielder Clint Frazier. The 25-year-old, who says he's taken heat on social media for his decision to wear a face covering at all times, drove a two-run homer into the second deck in the fourth inning.

The Cleveland Indians loaded into three buses Saturday for the 2-hour-plus drive to Pittsburgh. Manager Terry Francona said the team adhered to social distancing guidelines — and staggered arrival times — for the team's first trip since camp reopened.

"I think it's a good experience for all of us," he said. "We're not used to getting on a bus and get your temperature taken and things like that, so it's good to go through that."

The Indians made a public show of support for social justice before their 5-3 win, standing with their right hands over their hearts and their left hands on the right shoulder of their teammates during the national anthem.

A few fans gathered outside PNC Park, hoping to catch some sort of game action.

Michael Kirkpatrick, 73, and his son, Zac, stood on the Clemente Bridge beyond center field — the same place they crammed shoulder to shoulder during the Pirates' National League wild-card game in 2013. No trouble finding a spot this time.

"I just need to hear a bat hit a ball," Zac said.

In Washington, a moment of silence was held for civil rights trailblazer and Georgia Congressman John Lewis, who died Friday. Players stood apart for the national anthem, an acoustic rendition by the U.S. Army Brass Quintet performed before Game 4 of last year's World Series and replayed on the video scoreboard.

"Definitely has a different feeling to it," Nationals center fielder Michael A. Taylor said.

Postgame handshake lines got a shakeup, too. The Yankees air-fived each other outside the dugout after finishing a 9-3 win, and Cleveland celebrated its victory by tapping toes with teammates.