Alvarez’s 446-foot blast in the fourth inning was the 36th ball to reach the river in PNC Park’s 14-year history but only the third to get there on the full, according to mlb.com.
Daryl Ward in 2002 and Garrett Jones in 2013 found water on the fly – but Alvarez’s blast landed in a small motor boat and was retrieved by a passing fan.
But it was in vain after the Twins scored six runs in the second inning, thanks to Joe Mauer’s three-run single and Trevor Plouffe’s two-run homer, and moved only half a game behind the Detroit Tigers in the American League Central.
Detroit suffered a shock 8-1 defeat to the Milwaukee Brewers as Anibal Sanchez gave up successive home runs to Ryan Braun, Adam Lind and Aramis Ramirez in the third.
Division leaders the Kansas City Royals beat the Cincinnati Reds 3-0 behind Yordano Ventura’s seven scoreless innings.
The Tampa Bay Rays pulled level with the New York Yankees atop the AL East with a 5-3 win over the Atlanta Braves, Asdrubal Cabrera with a home run.
The Yankees lost 8-6 in 10 innings to the Washington Nationals, Ryan Zimmerman with the walk-off homer.
The Houston Astros used home runs from Chris Carter, Colby Rasmus and Jason Castro to win 6-4 against the Oakland Athletics – who at 14-27 are the only team in MLB with a worse record than Milwaukee this season.
AL West leaders Houston remain 5.5 games clear of the Los Angeles Angels, who beat the Toronto Blue Jays 3-2.
The Baltimore Orioles beat the Seattle Mariners 9-4 despite a three-run homer from ex-Oriole Nelson Cruz, while the Boston Red Sox beat the Texas Rangers 4-3.
Washington’s win saw both New York teams reeled in at the top of their divisions, with the Mets’ 10-2 loss to the St Louis Cardinals allowing the Nats to move level in the National League East.
Randal Grichuk drove in three runs and the Cards continue to lead the NL Central, with their 26-13 record the best in MLB and now 4.5 games clear of the Chicago Cubs who lost 4-3 to the San Diego Padres.
The San Francisco Giants beat NL West leaders the Los Angeles Dodgers 2-0 to close the gap to 3.5 games.
The Colorado Rockies beat the Philadelphia Phillies 6-5, the Arizona Diamondbacks won 4-2 against the Miami Marlins and the Cleveland Indians beat the Chicago White Sox 3-1.