Kyle Schwarber equalled an MLB record after homering three times in the Washington Nationals' 5-2 win over the New York Mets on Sunday.
Schwarber hit a lead-off home run to start the game, adding further homers in the fifth and the seventh innings.
The trio of homers means Schwarzer has hit five home runs in his past two appearances, tying the major league record over a two-game span.
Schwarber also set a franchise record with nine homers in a 10-game span, moving up to 18 for the season.
"To be honest with you, I don't know what's going on,'' Schwarber said.
He added: "I'm a big believer that hitting is a feeling. Don't get me wrong, there's mechanical, there's approach, things like that but when you step in the box and everything feels right, you already have a big advantage.''
Acuna reaches century
Ronald Acuna Jr. also reached rare territory as the Atlanta Braves bounced back with a 1-0 win over the St Louis Cardinals in the second game of their doubleheader. After losing the opener 9-1, Acuna – who turns 24 in December – hit the decisive homer in the third inning of the second game, registering the 100th in his career. He joins an exclusive list of players who have hit 100 homers and 70 stolen bases before the age of 24 in the modern era, alongside Mike Trout, Alex Rodriguez, Andruw Jones and Ken Griffey Jr.
Shohei Ohtani homered again to move into the joint lead for the most home runs this season, alongside Toronto Blue Jays sensation Vladimir Guerrero Jr., with the 23rd of the campaign. The Los Angeles Angels still lost 5-3 to the Detroit Tigers.
Future Hall of Famer Albert Pujols hit the 673rd homer of his career in the Los Angeles Dodgers' 9-8 triumph at the Arizona Diamondbacks.
The Houston Astros made it seven consecutive wins with their 8-2 victory over the high-flying Chicago White Sox, while the Colorado Rockies hit four homers in one inning but lost 7-6 to the Milwaukee Brewers.
Shed Long hit a rare walk-off grand slam as the Seattle Mariners beat the Tampa Bay Rays 6-2 and completed a sweep over the defending American League (AL) champions.
Padres sweating on Tatis injury
The National League's home run leader Fernando Tatis Jr. exited early after an injury to his left shoulder as the San Diego Padres completed a sweep over the Cincinnati Reds with a 3-2 win –the team's first four-game sweep of any franchise since 2011. Tatis hurt the shoulder, the same one which troubled him in spring training, while diving in the field.
Yankees' triple-play to clinch win
The New York Yankees finished their 2-1 win over the Oakland Athletics in style with a triple play. It was a record-tying third triple play for the Yankees this season, with Sean Murphy hitting straight to third to initiate the trio of outs. A's manager Bob Melvin said. "I've never seen a game end like that before."
Sunday's results
Toronto Blue Jays 7-4 Baltimore Orioles
New York Yankees 2-1 Oakland Athletics
Cleveland Indians 2-1 Pittsburgh Pirates
Washington Nationals 5-2 New York Mets
Kansas City Royals 7-3 Boston Red Sox
Houston Astros 8-2 Chicago White Sox
St Louis Cardinals 9-1 Atlanta Braves
Chicago Cubs 2-0 Miami Marlins
Minnesota Twins 4-2 Texas Rangers
Milwaukee Brewers 7-6 Colorado Rockies
Philadelphia Phillies 11-2 San Francisco Giants
Detroit Tigers 5-3 Los Angeles Angels
Los Angeles Dodgers 9-8 Arizona Diamondbacks
San Diego Padres 3-2 Cincinnati Reds
Seattle Mariners 6-2 Tampa Bay Rays
Atlanta Braves 1-0 St Louis Cardinals
Dodgers at Padres
The in-form Dodgers (44-27) make the short trip to take on the Padres (42-32), who swept their four-game series against the Reds but have dropped five of their past 10 games and may be without Tatis.