Swansea has a number of chances with Nathan Dyer forcing a diving save from Brad Friedel inside five minutes before Sinclair curled his 23rd minute attempt just over the crossbar from outside the area.
Tottenham were on the back foot during the first half but managed to go ahead late when Benoit Assou-Ekotto's cross from the left deflected into the path of Rafael van der Vaart who controlled with his chest before slotting home with help from a touch off Swans defender Ashley Williams.
Early in the second half, van der Vaart squandered a good chance from Emmanuel Adebayor's through ball but Michel Vorm was equal to the task but in the end, Swansea got a deserved point when Sinclair finished with six minutes remaining. Substitute Angel Rangel sent a low ball in from the right which took a touch off Assou-Ekotto and somehow evaded Friedel with Sinclair unmarked with an open goal in front of him to keep Swansea's record at home to just one loss enabling them to retain 14th on the table.
The draw left Tottenham third on the table at the turn of the year, sitting six points behind second-placed Manchester United with a game in hand.
TRIBAL ASKS: Is it results like this that will deny Spurs from making a genuine title push and on the back of this performance, are Swansea capable of staying in the top flight?
Liberty Stadium, Swansea - 20,393