Chase won last Saturday's opening two junior 250cc races and settled for fifth in his final outing, after crashing, enough to secure the class win at Woodville, leading Winton's Kyle Hartley and Levin's Billy Frank to the top of the podium.
This result was more the remarkable for Chase because it was his first ride back since recovering from a wrist injury he sustained last Labour Weekend.
"That fact actually made me quite nervous," said Chase, who is shortly due to start as a Year-11 pupil at Taupo's Tauhara College.
"I managed to get awesome starts and felt really comfortable and fast on the bike. I love the new Yamaha.
"I crashed while leading in the last race and bent my handlebars but I made up four places in one lap ... I knew I had to go hard."
Motocross talent runs in the Chase family. Cohen Chase's younger brother, Wyatt, is also a champion racer, having won the national title in the junior 13-16 years' 85cc class at the 2013 New Zealand TT Championships, and he is also very likely to be a champion again before the year is over.
Wyatt Chase finished overall runner-up, behind fellow Yamaha star Reece Walker, of Nelson, in the 12-14 years' 125cc class at Woodville.
Walker scored a hat-trick of wins, while Wyatt Chase finished 2-2-3. Te Puke's Tyler Steiner finished 4-3-2 for third, Feilding's Tony "T-Bone" Cvitanovich finished 3-4-4 and Masterton's Camden Butler finished 6-5-5 to round out the top five.