CHICAGO (CBS) — The Chicago Bulls tipped off the preseason Monday night against the Milwaukee Bucks’ B-team.

The most glaring area the Bulls need to improve upon, their defense, remains a work in progress.

This was just game one of the five preseason tune-ups for Coach Jim Boylen’s troops.

Zach Lavine led the way for the Bulls early. He blew by former teammate Robin Lopez for a dunk, and finished the game with 16.

The rookies also made their debut – Coby White and Daniel Gafford each had 12 points, while showing the speed the Bulls liked when they took him at seven overall.

Gafford also showed off his athleticism on an alley-oop dunk from Denzel Valentine. It was Valentine’s first game in a year.

The Bulls lost 122-112.