A brace from Rebecca Jane was enough to secure the Royals all three points away at Tottenham.
Despite missing injured top scorer Fran Kirby, who will be out for a month after fracturing her ankle, the Royals made a vibrant start to the match and created a number of half chances early on. Jane first struck just wide, before so very nearly finding Donnelly with a dangerous cross.
Spurs had a golden opportunity themselves, but Grace Moloney came to Reading's rescue by denying the Tottenham striker one-on-one before half time.
Straight from the restart, Jane went agonisingly close when her effort struck the post - with Harriet Scott unlucky not to convert the rebound.
But our pressure eventually paid dividends when Donnelly found the top corner of Tottenham's goal after 50 minutes.
Minutes later, the lead was doubled. Lois Roche found Jane, who gave Spurs' goalkeeper no chance with a sweet volley into the bottom corner.
She soon had a chance to get her second when Roche and Donnelly combined to set Jane up, but her shot skinned the bar. Alice Palmer was next to go close, but her header was parried away well by the 'keeper.
Spurs were hanging on, and it got worse for them when their midfielder lashed out at Moloney after a collision with the goalkeeper - and was shown a straight red.
But this seemed to spark the hosts into life, who pulled one back with time running out. Tottenham drifted in a dangerous free kick, the referee spotted some shirt pulling and pointed to the spot.
The skipper converted the spot kick, but Reading's Women stood firm for all three points which cements their position at the top of the league.