Mike

Engine torque has a stronger effect when you pitch the nose up
with elevator, and the airplane wants to pull to the left.
I myself am learning to deal with this by applying some right
rudder, which causes the plane to hold a straight vertical line.
Others will mix in some right rudder to advanced throttle positions,
as you use more throttle when going vertical.
Try one or the other or both... you'll be glad you did..

Gerald