Ionescu earned the honor with yet another outstanding season. The Ducks star averaged 17.5 points, 9.1 assists and 8.6 rebounds, shooting 51.8 percent from the field and 39.2 percent from three-point range.
Her final season in Eugene was highlighted by a historic feat, as she became the first player in NCAA Division I history to record at least 2,000 points, 1,000 assists and 1,000 rebounds in a career.
As Lindsey Wisniewski of NBC Sports Northwest noted, Ionescu becomes the first player in program history to capture the award.
Second-ranked Oregon finished the season at 31-2.
Toppin beat out four other finalists who were announced March 17 to become the first player in Dayton history to win the award. He was the only sophomore among the finalists that also included seniors Udoka Azubuike (Kansas), Myles Powell (Seton Hall) and Payton Pritchard (Oregon), as well as junior Luka Garza (Iowa).
The award was well-deserved.
The high-flying playmaker led Dayton to a 29-2 overall record and perfect 18-0 mark in Atlantic 10 play. He became the first player in Flyers history to win Atlantic 10 Conference Men's Basketball Player of the Year and impressed on the big stage a number of times this season.
He poured in a combined 49 points in back-to-back wins over power-conference foes Georgia and Virginia Tech in November, just missed a double-double with 18 points and nine rebounds against Kansas, and scored a combined 42 points in two wins over Rhode Island, which finished in second place in the conference.
In all, Toppin averaged 20.0 points, 7.5 rebounds, 2.2 assists, 1.2 blocks and 1.0 steals per game while shooting 63.3 percent from the field and 39 percent from three-point range.
Attention now turns to his next step and whether he will be as dominant in the NBA.
Bleacher Report's Jonathan Wasserman projected Dayton's leader to go No. 8 overall in a March mock draft and noted: "It's getting harder to keep downgrading Toppin due to the level of competition or defensive questions. He's been too effective offensively given the improved shooting and advanced passes that continue to pop."
That skill set won him college basketball's most prestigious individual award.