WASHINGTON -- Elena Delle Donne scored 25 points, making WNBA history along the way, and the regular-season champion Washington Mystics raced past the Chicago Sky 100-86 on Sunday.

She became the first player in WNBA history to shoot over 50% from the field (220 of 427), 40% from 3-point range (52 of 121) and 90% from the foul line (114 of 117). Her free throw percent of 97.4 is a record for a player with at least 100 attempts.

The Mystics (26-8), who lost to Seattle in the finals last year), have a double-bye into the semifinals and home court advantage throughout the playoffs. The Sky (20-14) are the No. 5 seed and play No. 8 Phoenix at home on Wednesday in the single-elimination opening round of the playoffs.

Chicago's Courtney Vandersloot had six assists to become the first player in league history to reach 300 in a season, which she did exactly, and the first player to average at least nine assists a game for a season (9.1).

Washington lead 56-39 at the half but Chicago cut the lead to six in the final minute of the third quarter. Tianna Hawkins answered with a layup for the Mystics and after a Sun miss Myisha Hines-Allen hit a 3 with 1.5 seconds left to restore the double-figure lead. Chicago never challenged in the fourth quarter.

Diamond DeShields led the Sun with 16 points. Allie Quigley added 13 with three 3-pointers, giving her a Chicago record 80 for the season.