The opening goal came on 13 minutes when 19-year-old Unal produced a quite stunning free-kick from range which caused deafening noise at De Grolsch Veste.
Unal now has five goals in four Dutch league outings following his hat-trick against FC Groningen last month while Kosovo international Celina scored for the second match in a row following last weekend's 3-1 loss at Heerenveen.
Yaw Yeboah, also on loan from City, played a full 90 minutes for the Enschede outfit.
Check out Unal's double below thanks to Football 24:
After the match, Unal spoke of life at Twente alongside his City colleagues.
"I feel at home here. If we can give the fans this every time, that's great," he told fctwente.nl.
"It's always good to be able to communicate with the players I know from Manchester City. If young players complement each other, that's good."
Twente now sit 10th on the Dutch top flight table with nine points from six matches.