A controversial offside decision denied Pompey Ladies as Spurs took the three points at Fratton Park.
The North London side led 2-0 at the break after making a strong start to the contest.
But the Blues stormed back in the second half.
Tiff Taylor scored to reduce the deficit.
Charley Wilson then swept home what appeared to be a well-deserved equaliser.
But she was denied her moment by an offside flag, as the raucous celebrations of 673 fans were cut short.
Spurs were then able to close out a hard-fought 2-1 victory.
Their success owed much to their impressive start to the contest.
They dominated the early exchanges, forcing Pompey back.
However, on seven minutes, totally against the run of play, Pompey almost took the lead.
Wilson sped away from the Spurs defence and crossed perfectly for Sarah Kempson, who saw her shot slam against the post.
Spurs made their early dominance count with the opener when Megan Wynne’s shot looped high into the net.
Nadine Bazan’s desperate attempt to head it off the line proved in vain.
Spurs doubled their lead on 21 minutes.
Tall striker Wendy Martin, a real menace throughout the first half, turned Victoria Summerfield in the box and managed to clip a shot goalwards.
The ball squirmed past Sadie Blakely and Andra Marcoci was quickest to react, to stab home at the far post.
Pompey came out fired up for the second half.
Kempson’s corner was almost fumbled into her own net by defender Kimberly Lane.
Spurs keeper Chloe Morgan managed to claw the ball off the line.
Pompey got the reward they deserved with a goal to cut the deficit on 70 minutes.
Kempson whipped in a superb corner and substitute Taylor got the touch to force the ball over the line.
Two minutes later, Lucy Quinn cut the Spurs defence to shreds with a stunning mazy run into the box.
She showed great composure to pick out Gemma Simmonds with her cut back.
But the same could not be said of the finish.
Simmonds lashed the ball over the top with the goal at her mercy. Pompey then sparked wild celebrations on 74 minutes.
Wilson’s superb first-time finish flashed into the back of the net but the crowd cheers quickly turned to jeers as a free-kick was awarded for offside.
Spurs launched a quick counter-attack as Pompey were still celebrating, having not heard the whistle because of the incredible noise in the stadium.
Fortunately it came to nothing and Pompey were able to regroup.
Spurs were then left clinging on for victory.
Simmonds saw her effort loop into the arms of Morgan before Quinn fired high and wide in the final act.
Pompey Ladies: Blakely, Simmonds, Bazan (Taylor, 46mins), Hunt (Bloomfield, 78mins), Murphy, Summerfield (Frampton, 44mins), Rutherford, Kempson, Hillier, Wilson, Quinn. Unused subs: Cox, McMillan.