Albion suffered four successive Premier League defeats for the first time since 2019 despite a second-half fightback at St James’ Park.
Resurgent Newcastle stretched their unbeaten run to eight games after early goals from Ryan Fraser and Fabian Schar set them up for a first Premier League win over Albion in ten attempts.
Lewis Dunk headed the visitors back into it ten minutes into the second half and the skipper nearly scored again with another header as Albion pressed for an equaliser. Leandro Trossard also went close but Newcastle hung on to claim their first win of the season against a side in the top half of the table at the start of play.
Albion had started the game well, after Fraser had tested Sanchez with an early volley.
Shane Duffy missed a great chance when he failed to get a clean connection on Pascal Gross’s inswinging corner before Danny Welbeck glanced another set-piece by the German midfielder narrowly wide.
But the mood inside St James’ Park changed dramatically as home fans celebrated two goals in as many minutes.
Fraser opened the scoring in the 12th minute, volleying home after Jacob Murphy had burst onto Chris Wood’s pass, sprinted into the box and dinked his shot over Sanchez. The ball came back off the post but straight to Fraser, who netted Newcastle’s first Premier League goal against Albion at St James’ Park.
The second came two minutes later when defender Schar met Fraser’s corner at the near post with a powerful header which Sanchez got a hand too but could not keep out.
Albion responded impressively. Steven Alzate, on the ground where he made his Premier League debut, had a close-range shot blocked and in the 28th minute Tariq Lamptey burst forward and found Welbeck, whose shot was kept out by Martin Dubravka.
But before the break Newcastle could have scored again. Dan Burn had his head in his hands after he nodded Fraser’s corner wide at the far post then Albion gave the ball away deep in their own half but Murphy fired straight at Sanchez.
Albion got back into the game ten minutes into the second half when Dunk beat Dubravka to Gross’s inswinger to head into an empty net from close range.
The home crowd were on edge, and Graham Potter shuffled his pack on the hour by introducing top scorer Neal Maupay and Solly March. Emboldened by his first goal of the season, Dunk nearly had a second in the 70th minute when Dubravka scrambled to his right to keep out another close-range header.
Albion kept pushing. Dubravka fell gratefully onto Leandro Trossard’s well-struck low drive after Solly March cut the ball back before Newcastle, relying on the speed of Alain Saint-Maximin, had a chance on the break but the Frenchman's shot was blocked by Dunk.
Sanchez came up for one attack deep into stoppage time, but Newcastle clung on.
Albion: Sanchez, Lamptey (March 59), Duffy, Dunk, Veltman, Cucurella, Alzate (Mac Allister 78), Gross, Trossard, Moder (Maupay 59), Welbeck.
Subs: Steele, Bissouma, Lallana, Caicedo, Roberts, Ferguson.
Referee: Martin Atkinson
Attendance: 52,214