Spurs remain in the top-flight for next season, thanks to a 1-0 win over Everton on Sunday. But Boro will not be joining them, as they suffered a heartbreaking late defeat to Hull City at Wembley Stadium.
Now, 23-year-old Hackney is expected to become one of Middlesbrough’s most sought-after assets this summer, with offers expected to start at around £20 million.
Hackney has just one year remaining on his current contract and is understood to be eager to test himself in the Premier League.
Spurs view Hackney as a player who fits perfectly into the recruitment model they are trying to build under their long-term strategy.
The North London side are keen to target emerging talent from across the English football pyramid while also balancing their squad with established, proven names capable of making an instant impact.
Hackney’s profile has attracted significant attention after another impressive campaign with Middlesbrough, where his technical quality, composure on the ball and energy in midfield have continued to stand out.
Tottenham are considering an approach, as they believe he could develop into an important option for the future while also adding immediate depth.
However, Spurs would be very unlikely to have a free run at the England Under-21 international.
Everton, Crystal Palace and Nottingham Forest are all among clubs seriously monitoring the midfielder closely ahead of the transfer window, with sides aware that Middlesbrough may now be forced into a sale.
Tottenham are determined to respond after a hugely disappointing campaign and see this summer as a key moment to reset the direction of the club.
A recruitment drive is designed to draw a line under this season's frustrations and rebuild a squad capable of challenging for European places again as early as next year.
Spurs are also exploring other additions in the market, and we revealed on Saturday how West Ham captain Jarrod Bowen could potentially arise as a target if the Hammers suffer relegation - which has now happened.
Tottenham are also facing decisions on player exits, with Cristian Romero and Guglielmo Vicario two of the higher-profile players expected to move on.