The Frenchman rounded Brad Friedel in the 13th minute to breach a Spurs defense that had not conceded a Premier League goal in nearly five hours of soccer.
The Dutchman was on fine form to deny Tottenham at regular intervals as Newcastle recorded its first away win over Spurs in five attempts, with Krul making 13 saves.
Loic Remy continued his fine form to put Newcastle ahead with just 13 minutes on the clock, latching onto Yoan Gouffran’s through ball before rounding Brad Friedel and slotting home his seventh league goal in as many appearances.
Roberto Soldado, Christian Eriksen and Paulinho were all frustrated by Krul in the first half before he continued his impressive performance after the break, with a spectacular double save among the highlights.
Andre Villas-Boas was forced to rest first-choice goalkeeper Hugo Lloris following the Frenchman's collision with Romelu Lukaku against Everton last weekend. Friedel made his 450th Premier League outing in his place while Mousa Dembele was favored over Sandro in midfield. Eriksen and Gylfi Sigurdsson were retained after impressive Europa League showings against Sheriff on Thursday.
Alan Pardew's Newcastle was unchanged from its Premier League win over Chelsea last weekend, but welcomed back captain Fabricio Coloccini, who was among the substitutes.
The home side made the brighter start and threatened after nine minutes when Soldado headed Eriksen's cross over the bar. Remy then found himself through on goal but was thwarted by a last-ditch tackle from Vlad Chiriches before Yohan Cabaye was denied at close range by Friedel.
The visitors' brief spell of pressure was rewarded when Gouffran dispossessed Dembele and played in Remy, who sped away from Michael Dawson, beat Friedel and calmly finished.
The home side should have leveled five minutes later when Eriksen curled an inviting delivery across the Newcastle goalmouth, but no Spurs player was on hand to apply a finish.
Roberto Soldado's header was then tipped over by Krul just short of the half-hour mark before the Dutchman was again alert to deny Eriksen and Paulinho before the break.
Krul was again on hand to maintain his side's lead four minutes into the second half, denying Eriksen one-on-one with his left leg, with substitute Sandro driving wide soon after.
The Netherlands international continued to deny Tottenham, making a fine double save on Sigurdsson's free kick and then Younes Kaboul's follow-up, as Spurs continued to apply plenty of pressure.Remy and strike partner Shola Ameobi were withdrawn as Pardew looked to shut up shop - a tactic that proved successful as the visitors denied Tottenham the chance of returning to the top four.