Chances were few and far between in the first half, with Newcastle’s struggling striker Joelinton going closest, heading against the crossbar.
Newcastle United claimed a first win in their last five Premier League games in dramatic style as Isaac Hayden headed a last-gasp winner to seal a 1-0 victory over top-four chasing Chelsea at St James' Park on Saturday.
Chances were few and far between in the first half, with Newcastle's struggling striker Joelinton going closest, heading against the crossbar.
After the break, Willian fired wide following a swift Chelsea counter, before Tammy Abraham missed the target after rounding Newcastle goalkeeper Martin Dubravka as the visitors remained frustrated.
Chelsea's leading goalscorer this season Abraham thought he had won it late on, but his flicked effort was cleared off the line by Matt Ritchie, another chance that went begging for the visitors.
Just as the game looked to be heading for a stalemate, Newcastle earned one last corner in stoppage time, with Hayden rising highest to meet the cross from Allan Saint-Maximin to send St James' into raptures.
The result moves Steve Bruce's side up to 12th in the standings on 29 points from 23 games, with Chelsea remaining in fourth place.
"We didn't score — it has been the story of part of our season," Chelsea boss Frank Lampard said. "We can't just rely on Tammy. We have to score goals across the front line."
Newcastle manager Bruce has lamented the long injury list he has had to work with of late, but three key players were back for Chelsea's visit with Jonjo Shelvey, Saint-Maximin and captain Jamaal Lascelles all fit to start.
That bad luck with injuries continued, however, as Jetro Willems was carried off on a stretcher early on.
Joelinton, who has one league goal since his becoming Newcastle's club record signing in the close season, headed against the crossbar in the 21st minute as the hosts took the game to Chelsea.
A superb pass from Reece James set N'Golo Kante up for the game's next chance, but the Premier League's most prolific shotstopper, Dubravka, made another timely save.
Chelsea created several openings after the break, only for poor finishing and determined defending keeping them from scoring.
Abraham, after twice going close, was substituted, looking frustrated as he walked off, but Chelsea still could not find the crucial breakthrough.
The deciding strike came after Ritchie's corner had been cleared, only for Saint-Maximin to cross brilliantly for Hayden to head home and give Bruce a second-ever win over Chelsea as a manager.
"Today we didn't seem to carry a threat," Bruce said. "But one great ball or delivery and you may call it smash and grab but it is good to see."