Gayle scored his fourth goal in three games for his new club to help Rafa Benitez's side win their second game in a row.
The striker latched onto a pass from Mohamed Diame and fired a half-volley home to give Newcastle the three points.
First win for Monk
Former Swansea boss Garry Monk got his first win as manager of Leeds United in the Championship's early kick-off.
Marcus Antonsson and Chris Wood both scored in the second half to help Leeds to a 2-0 victory over Sheffield Wednesday.
Wolves win from behind
Wolves fought back to beat local rivals Birmingham City to continue their impressive start to the Championship season.
Che Adams put Birmingham ahead in the 24th minute, but Wolves produced an impressive second half fightback.
Goals from Joe Mason (47), Danny Batth (61) and Jon Budvarsson (89) helped Wolves to a 3-1 win.
Blackburn still struggling
Blackburn's poor start to the season continues as they failed to beat newly-promoted Burtoin Albion at home.
Craig Conway put Owen Coyle's side ahead in the 25th minute, but Jackson Irvine equalised for Burton in the 43rd minute.
Sam Gallagher looked to have won the game for Rovers in the 61st minute, but Tom Naylor scored a late equaliser for the visitors.
Fulham steal late draw
Fulham stole a late draw against Cardiff thanks to a goal from Kevin McDonald.
Ryan Sessegnon put Fulham 1-0 up in the 44th minute, but goals from Joe Ralls (60) and Anthony Pilkington looked to have won the game for the Welsh side, until McDonald struck late on to tie the match at 2-2.
Huddersfield continue impressive form
Huddersfield left it late to beat Yorkshire rivals Barnsley. Chris Lowe put the Terriers in the lead in the first half, but Alfie Mawson scored just after half-time to level the scores.
However, Jonathan Hogg won the game for Huddersfield in the second minute of injury time to keep the Terriers top of the Championship.
'On fire' Will Grigg can't prevent Wigan from losing
Northern Ireland's viral sensation scored twice against Nottingham Forest, but Wigan still went down 4-3 to their Championship rivals.
Assombalonga put Forest 1-0 up early on, but Michael Jacobs equalised for Wigan just five minutes later.
Oliver Burke and Will Grigg both scored second half braces for Forest and Wigan respectively, but it was Thomas Lam who won the game for the home side in injury time.
Preston get valuable win away at QPR
Preston got their first poinst of the season as they beat QPR at Craven Cottage.
Beckford put Preston ahead in the first half, and Nedum Onuoha scored an own goal just after half-time to give Preston a 2-0 win.
All square between Reading and Brighton
John Swift put Reading ahead in the 2nd minute, before Joey van den Berg scored an own goal in the eight minute.
Anthony Knockaert put Brighton 2-1 up just after half-time, but Paul McShane salvaged a point for Jaap Stam's side just before the hour mark.
However, Van den Berg's day got even worse in the 90th minute as he was sent off for bringing down Tomer Hemed.
Rotherham get vital win against Brentford
Alan Stubbs got his first win as Rotherham manager as his side beat Brentford 1-0.
Danny Ward scored the only goal of the game to help his side get their first win of the season.