Sinclair has told England Under-21 boss Stuart Pearce: You ain't seen nothing yet.
The in-form Swansea star missed a call-up to Pearce's squad following a hamstring injury.
But the winger, 21, aims to impress for the visit of league leaders QPR.
Sinclair admitted: "It was really frustrating as the injury cost me a spot in the squad. Hopefully I can keep playing well, win games for Swansea and get the call-up."