In contrast, Spurs boss Mauricio Pochettino left Tyneside having seen a satisfactory performance from his men, who were eventually rewarded for their patience.
Rafa Benitez brought on Jamaal Lascelles and Chancel Mbemba as replacements for the two defenders.
Harry Kane's tackle on Lejuene forced Benitez to take off the Frenchman.
Dele Alli scores past Rob Elliot.
The combative midfielder was trying to get the ball back quickly, Alli moved it away and Shelvey reacted by treading on Alli's ankle.
A deflection off Matt Ritchie saw Eriksen's pass loop up for the unmarked Kane inside the box, but Elliot stayed big and blocked his powerful strike in the 51st minute.
With 20 minutes left, Ben Davies was found by Eriksen with the Welshman scoring the second goal of the game.
The club's last Premier League game came against Spurs, with the Magpies already relegated and the north Londoners aware that a victory would see them finish above Arsenal. - Jonjo Shelvey was the first Newcastle player to be sent off on the opening day of a Premier League season at St. James' Park since Alan Shearer in 1999. "It's more unsafe. We lost one player from that", Benitez told BBC Sport. He was also red carded in a Championship match at Nottingham Forest in December 2016.
His options have improved, though, with young right back Kyle Walker-Peters impressing on his first league start and South Korea forward Heung-min Son making a return to action after sustaining a broken arm in preseason.