KANSAS CITY — Finally.

The Royals’ mostly dormant offense in 2020 awoke on Thursday night with a fair share of pent-up anger. The unsuspecting victim was the Cubs’ pitching staff as every Kansas City hitter reached base at least once en route to a 13-2 victory at Kauffman Stadium.

The Royals snapped a six-game losing streak.

Right-hander Brad Keller, making his first start of the season after being activated from the COVID-19 injured list, was the beneficiary. Keller threw five shutout innings, giving up three hits while striking out seven.

Meanwhile, the Royals pummeled Cubs starter Tyler Chatwood, who entered the game 2-0 with a 0.71 ERA. They chased him with one out in the third after racking up 11 hits and eight runs.

The list of offensive highlights is a long one:

• Ryan O’Hearn snapped a 0-for-11 stretch with an RBI single in the first, then added an RBI double in the fifth.

• Whit Merrifield belted his fourth homer of the season, a two-run shot off the left-field foul pole. Merrifield stole a base and scored three times.

• Adalberto Mondesi got the Royals’ six-run third going with an electrifying hustle double — Statcast clocked his sprint speed at 30.5 ft/sec, which is classified as elite.

• Salvador Perez had three hits, including two doubles and two RBIs.

• Jorge Soler had three hits, including his third home run.

• Maikel Franco doubled and homered, his third jack of the season.

• Rookie Nick Heath got his first big-league hit, an RBI double in the third inning.

Keller was on top of his game from the start. He retired 10 of the first 12 hitters he faced, striking out five on 75 pitches (52 strikes). Keller’s four-seamer and sinker were just effective enough to set up his slider; he threw his slider 22 times and got eight swings and misses and two called strikes.