Newcastle dented Arsenal’s title hopes on Saturday, winning 1-0 and giving leaders Manchester City the opportunity to move eight points clear of the Gunners at the top of the Premier League.
Alexander Isak scored the game-winning goal in the 12th minute, heading in Anthony Gordon’s perfect cross from the right.
Arsenal struggled to get out of first gear and, despite dominating possession, managed only one shot on target throughout the game.
Mikel Arteta’s men have now picked up only one point in their last three games, as their title hopes are swiftly fading.
If reigning champions City win against Bournemouth later on Saturday, they will be eight points ahead of Arsenal. Liverpool, one point behind City, hosts Brighton at Anfield.
Arsenal has pushed Pep Guardiola’s City hard in each of the previous two seasons and appeared to be well prepared for another title assault, but the margin is now disturbingly large.
The injury-hit visitors got off to a good start at St James’ Park, with Leandro Trossard pulling the ball wide.
But the host team, which had not won in five games, rapidly calmed, and Sweden forward Isak squeezed between Gabriel and William Saliba to head home Gordon’s magnificent first-time cross.
Bukayo Saka, an Arsenal winger, lacked penetration but headed wide in the 18th minute after rising over his man.
Newcastle defender Lewis Hall blocked Mikel Merino’s attempt on the line after a Declan Rice corner caused havoc, but the visitors lacked rhythm and were unable to match the home team’s intensity.
Arteta chose not to make changes at halftime, and Newcastle came near to increasing their advantage almost immediately, with Joe Willock’s shot saved by David Raya.
Just after the hour mark, the Spanish manager substituted 17-year-old Ethan Nwaneri and Oleksandr Zinchenko for Gabriel Martinelli and Merino, respectively.
Isak launched a shot at Raya, which the Arsenal goalkeeper blocked, before Rice muscled his way into the Newcastle area and struck wide.
Arteta made more changes, bringing on defender Ben White and striker Gabriel Jesus in a desperate attempt to equalise.
Arsenal struggled to gain momentum as the clock ticked down, but they lost a fantastic opportunity to equalise when Rice headed narrowly wide from a Saka cross in stoppage time.
The Gunners, who are still without captain Martin Odegaard, suffered a shock defeat to Bournemouth last month and drew 2-2 with Liverpool last week.
They have challenging games against Inter Milan in the Champions League and Chelsea next week.
The result moves Eddie Howe’s Newcastle to seventh in the table ahead of Saturday’s late kick-offs.