KANSAS CITY — The calendar has flipped to June, but Andrew Benintendi is still hitting like it is May.

The Royals’ left fielder crushed his second career grand slam on Tuesday night, pushing his team to a 10-5 win over the Pirates and a two-game series sweep of its Interleague opponent at Kauffman Stadium.

Benintendi came to the plate with the bases loaded and none out in the fifth inning against Pittsburgh starter Wil Crowe. On the first pitch, Crowe tried jamming Benintendi with an inside fastball, but Benintendi shortened his swing and jumped on it, sending it into the Royals’ bullpen a projected distance of 393 feet, according to Statcast.

It was Benintendi’s first home run at Kauffman Stadium in a Royals uniform — all four of his previous homers this season were on the road. Three of them came in May, the month that all the work he’s put into his swing paid off: Benintendi finished May with a .340 average and an .821 OPS after beginning the year hitting .225 and posting a .624 OPS in April. On the first day of June, he put together his fourth career five-RBI game with a slam and an RBI single in the first inning.

The Royals’ lineup had quite the 1-2 punch, with Benintendi hitting third and Salvador Perez, who had his seventh career two-homer game, hitting fourth. Leadoff man Whit Merrifield had three hits, and at the bottom of the order, Michael A. Taylor tripled and Nicky Lopez walked twice.