The Boston Red Sox have the best record in baseball (21-8, tied with the Diamonbacks), but probably should be one game better than that after losing a 13-inning marathon to the Kansas City Royals on Tuesday night.

Boston lost 7-6 at Fenway park, but had multiple chances to win the game. Closer Craig Kimbrel blew the save in the ninth inning, giving up a solo home run to Alex Gordon. The teams traded single runs in the 12th to make it 4-4, and a three-run blast by Royals outfielder Jorge Soler in the 13th put the game out of reach —  a mini rally was snuffed out by the Royals in the bottom of the inning.

Manager Alex Cora was furious after the game, citing his team’s poor defensive showing. The Red Sox committed four errors on the night, jumping their season total from eight (which was the best in the league) to 12 (now sixth-best in MLB).

“Awful, awful,” Cora said. “That was an awful game, yeah. Yeah. We were lucky we were playing 13 innings, honestly. That was bad. Mental mistakes, physical mistakes, all kinds of mistakes, that was awful.”

Rafael Devers, Christan Vasquez (twice), and Xander Bogaerts picked up the errors on the night, giving the Royals just enough offense to escape with a win against the high-powered Red Sox.

The Red Sox rocketed out to a 17-2 start, and finished April with a 20-6 record. However, they are just 4-6 in their last 10 games and may finally be returning to Earth.