CHICAGO -- The Royals entered the eighth inning Monday night searching for any kind of offensive momentum and trailing by three runs.

The deficit became one with back-to-back homers from Hunter Renfroe and MJ Melendez.

And Bobby Witt Jr. made sure to flip that momentum in a grand way.

With the bases loaded and two outs, Witt crushed the first pitch he saw from White Sox reliever John Brebbia -- a low slider -- out to the seats in left-center field and lifted the Royals to a 8-5 series-opening win over the White Sox at Guaranteed Rate Field.

After Renfroe and Melendez homered off righty Steven Wilson, Maikel Garcia singled to force Wilson out of the game and bring in Brebbia. Pinch-hitter Adam Frazier got hit on the 10th pitch of his plate appearance, and Michael Massey worked a six-pitch walk to load the bases for Witt.

Witt didn’t want to see as many pitches as the two hitters before him. He was ready to go from the jump, hitting that slider 98.8 mph off the bat and 384 feet for his 19th home run of the year, bringing his RBI total up to 75, tied for sixth in the Majors.

Tying a career high in hits with four on Monday, Witt’s hit streak is now up to 11 games. It was his third career grand slam.

The six-run eighth inning picked up the Royals’ pitching staff, including starter Alec Marsh, who allowed two runs in 4 2/3 innings Monday. In the bottom of the fifth, he had nobody on with two outs but hit Nicky Lopez, walked Andrew Vaughn and allowed the game-tying hit to Luis Robert Jr. Lefty reliever Angel Zerpa got out of the inning but then allowed two runs in the sixth inning, and Chris Stratton allowed a solo homer in the seventh.

Armed with a three-run lead in the ninth inning, closer James McArthur had a 1-2-3 outing, bouncing back from a tough couple of outings in which he allowed eight runs in his last two appearances. But he couldn't have done it without Witt, who made two incredible defensive plays from the outfield grass to take away hits in the ninth.