Dansby Swanson hit a grand slam and Pete Crow-Armstrong headlined a historic night on the basepaths for the visiting Chicago Cubs, who pummeled the Pittsburgh Pirates 18-8 on Monday to open a three-game series.

Crow-Armstrong had three of Chicago's eight stolen bases, the most steals in a game for the Cubs since 1913. Ian Happ had two, while Cody Bellinger, Nico Hoerner and Seiya Suzuki each had one.

The Cubs' 18 runs were a season high, as were their 21 hits. No. 9 hitter Miguel Amaya recorded his first career four-hit game and added four RBIs, and Suzuki also had four hits as Chicago won for the seventh time in its past 10 games.

Cubs starter Jameson Taillon (9-8) allowed four runs on eight hits without issuing a walk while striking out three over 6 2/3 innings against his former team.

Chicago stole seven bases against Pittsburgh starter Mitch Keller (11-8), who was pulled after throwing 97 pitches across four frames. The right-hander surrendered three runs on seven hits to go along with two walks and four strikeouts.

The Cubs carried a 3-2 lead into the sixth inning before exploding for eight runs -- including six with two outs -- against Pirates reliever Domingo German.

Chicago's first three batters of the inning reached, with Amaya doubling home Swanson and Crow-Armstrong to make it 5-2. Amaya came home on a two-out single from Suzuki, who later scored on Hoerner's bases-loaded walk.

Swanson capped the Cubs' big inning with a 405-foot drive into the left field seats that made it 11-2. German was charged with eight runs on six hits and four walks in 2 2/3 frames.

Isaac Paredes added a solo shot for Chicago in the eighth before Pittsburgh plated a pair of runs in the bottom half of the inning. The Cubs tacked on six more runs in the ninth, which featured a relief appearance from Pirates first baseman Rowdy Tellez. Connor Joe's two-run shot in the ninth for Pittsburgh closed the scoring.

Chicago jumped ahead 2-0 in the second inning on two-out RBI singles from Crow-Armstrong and Amaya. Consecutive doubles from Suzuki and Bellinger to start the third made it 3-0 before the Pirates pulled within 3-2 in the bottom of the frame.

Jared Triolo tripled to begin the inning and scored on Ji Hwan Bae's groundout, and Bryan Reynolds roped a two-out solo shot to right.

--Field Level Media