While Tottenham's 2-0 win at St. James' Park looked rather routine in the end, Rafa Benitez's side performed well for much of the game and managed to keep Spurs' devastating attack at bay.
There was nothing to be gained from standing on Alli, and Shelvey's action left his team in a tight spot, souring their first game back in the top flight.
Nine minutes later, Eriksen ran into the area but was beaten to the ball by Davies, who tucked a close-range finish under goalkeeper Rob Elliot.
Spurs started off slowly but looked assured and unsafe going forward after Shelvey's game-turning dismissal.
However, it needed Sissoko to depart the pitch for South Korean Son Heung-min before Tottenham took the lead and the Frenchman was heavily criticised while he was out on the pitch.