The two sides met at Elland Road on Saturday, with the visitors returning to the North East with a vital three points courtesy of a Jonjo Shelvey free-kick in the second half.
But while Toon fans might have been smiling on the way home, some say they had a less happy experience attempting to get inside the Yorkshire ground in time for kick-off.
Following the match, the Newcastle United Supporters’ Trust (NUST) posted an appeal on social media for anyone who witnessed “problems getting into the away end” to get in touch.
Since then, both Leeds United and West Yorkshire Police have confirmed they are probing events on Saturday afternoon.
A club spokesman said: “The club acknowledges the complaints raised by some Newcastle United supporters regarding issues experienced entering Elland Road on Saturday.
“Leeds United will now work with the Newcastle United Supporters Trust, West Yorkshire Police and our own safety team to review the issues raised and ensure we continue to provide a safe environment for everyone attending our stadium.
“We will not make any further comment until a review is complete.”
A spokesman for the force added: “We are aware of issues at the Leeds United v Newcastle United game at Elland Road on Saturday that resulted in congestion at the entrance points for away fans.
“We are currently liaising with the club to review the circumstances.”
Following the online appeal for information, the Leeds United Supporters' Trust also pledged its own support in probing the incident.
“It’s good that Leeds want fans to be involved [in the process],” said an NUST spokesman.
“Taking the fans’ thoughts on board is really important, it’s not taking away from the seriousness of the situation and it’s good that they want to rectify anything that went wrong.”
The Magpies’ away win in Yorkshire is just the team’s second victory so far this season.
And while the visitors’ performance led home manager Marcelo Bielsa fuming over “time wasting”, it prompted former Premier League legend Alan Shearer to tip new signing Kieran Trippier as a future captain.