Wednesday's report claims the Ajax defender's agent has confirmed talks are underway between the two clubs on a deal that would cost Spurs just over $11 million (US).
Tottenham tried to bring Vertonghen to White Hart Lane during the January transfer window, but Ajax refused to sell him until the summer.
Arsenal had appeared to gain the upper hand when Metro reported yesterday the Gunners had opened talks on a deal of their own for the Belgian international.
Now Ajax appear to be in the enviable position of playing one rival off the other to drive the final price up.
The 25-year-old central defender has scored seven goals during 29 league appearances for Ajax this season.
More important than his goals, Vertonghen's attack-mindedness and ability on the ball will allow whichever club lands him a great deal of flexibility in tactics and personnel along their defensive line next season.
Arsenal and Tottenham will both look to wrap up their deals quickly as they are not the only clubs sniffing around Amsterdam.
Chelsea and Newcastle are both rumored to be interested in Vertonghen as well.
For his part, Vertonghen has indicated the importance of Champions League football to his future.
Arsenal, Tottenham, Chelsea and Newcastle are all alive in the race to secure the last qualifying places, but each team could also finish completely out of European competition next season.
With that in mind, the final few dates in the Premier League calendar might do as much to determine Vertonghen's future as the negotiators sitting around the table.