Sam Kerr scored a league-record 18 goals this season. (Mike DiNovo-USA TODAY Sports)

It was no secret that Sam Kerr led the National Women’s Soccer League in goal-scoring this season — for the third year in a row.

She finished with a league-record 18 goals in 21 games while adding five assists.

On Friday, the NWSL made it official, declaring the Chicago Red Stars forward the Golden Boot winner.

Kerr already held the season record, setting the mark when she scored 17 goals for Sky Blue FC in 2017.

She became the first player in league history to finish three successive seasons as the league’s Golden Boot recipient.

The Australian international scored her record-tying and record-breaking goals in a 3-1 win over the Washington Spirit Sept. 22 in the Red Stars’ penultimate contest of the regular season.

North Carolina Courage forward Lynn Williams (12 goals) finished as runner-up in the scoring race for a second consecutive season.

Kerr has scored 51 league goals the last three seasons.

Chicago and Kerr will take on Portland Thorns FC in the NWSL semifinals Sunday at 3:30 p.m.

Here are some key numbers about Kerr:

* Seven of her goals goals this season were assisted by Yuki Nagasato

* Nine came at home, eight on the road

* Kerr played 1,862 minutes, scoring a rate of 103.4 minutes per goal

* She tallied 15 goals with her right foot, three with her left

* Sixteen of the goals were inside the box, two goals were outside

* She scored against every team in the league

* Kerr recorded a hat-trick, on the road vs. Orlando Pride

* She took 80 shots (excluding blocked shots) as 53 were on target, according to Opta

Every Sam Kerr goal scored in this season:

Goal 1: April 13 at North Carolina, 1-1 draw | 26′ | Assist: Yuki Nagasato

Goal 2: April 20 vs. Portland Thorns, 4-4 draw | 20’ | Unassisted

Goal 3: May 12 vs. North Carolina Courage, 3-1 win | 13’ | Assist: Yuki Nagasato

Goal 4: May 12 vs. North Carolina Courage, 3-1 win | 90+3 | Unassisted

Goal 5: May 19 at Houston Dash, 2-1 win | 8’ | Assist: Michele Vasconcelos

Goal 6: May 19 at Houston Dash, 2-1 win | 13’ | Assist: Vanessa DiBernardo

Goal 7: June 30 at Orlando Pride, 3-2 win | 7’ | Unassisted

Goal 8: June 30 at Orlando Pride, 3-2 win | 45 + 2 |Assist: Yuki Nagasato

Goal 9: June 30 at Orlando Pride, 3-2 win | 55’ | Assist: Michele Vasconcelos

Goal 10: July 21 vs. North Carolina Courage, 2-1 win | 58’ | Assist: Katie Jonson

Goal 11: July 28 at Reign FC, 4-0 win | 81’ | Assist: Katie Johnson

Goal 12: August 3 vs. Utah Royals, 2-0 win | 5’ | Unassisted

Goal 13: August 14 at Sky Blue, 1-0 loss | 90 + 1’ | Assist: Yuki Nagasato

Goal 14: September 8 vs. Houston Dash, 3-0 win | 7’ | Assis: Morgan Brian

Goal 15: September 8 vs. Houston Dash, 3-0 win | 44’ | Assist: Yuki Nagasato

Goal 16: September 15 at Sky Blue, 3-0 win | 33’ | Assist: Yuki Nagasato

Goal 17: September 21 vs. Washington Spirit, 3-1 win | 9’ | Assist: Kate Johnson

Goal 18: September 21 vs. Washington Spirit, 3-1 win | 49’ | Assist: Yuki Nagasato