Newcastle United claimed a stunning 4-1 win over Paris Saint-Germain on Wednesday in their first Champions League match at St James' Park in 20 years, while holders Manchester City scored two late goals to get the better of RB Leipzig.

Elsewhere in Europe's elite club competition there was a victory for Barcelona in Xavi Hernandez's 100th game as coach and an agonising last-gasp defeat for Celtic against Lazio.

But Newcastle stole the show on a night to remember for their fans on Tyneside as Miguel Almiron, Dan Burn, Sean Longstaff and Fabian Schaer all scored to inflict on the French club their heaviest Champions League group-stage loss since the Qatari takeover of 2011.

It could have been very different for the French champions had Dembele's sweetly-struck volley form Mbappe's cross found the net rather than flying inches wide early on. But once the home side, roared on by a raucous 52,000 fans, got their claws into the visitors, they did not let go.

Newcastle go top of Group F and PSG are second after rivals Borussia Dortmund and AC Milan played out a 0-0 draw in Germany.

Reigning champions City, meanwhile, are well on course to qualify for the knockout stages after successfully negotiating their hardest test in Group G to beat Leipzig 3-1 away. Phil Foden finished off a fine move to put City ahead midway through the first half, only for Lois Openda to equalise just after the interval.

But with Leipzig focused on talisman Erling Haaland, who scored five in 60 minutes the last time these sides met, it was the Norwegian's understudy Alvarez who scored the crucial goal, curling in City's second just five minutes after being introduced. Doku sealed the win with a goal in injury time.

Red Star Belgrade and Young Boys got off the mark in the same group with a 2-2 draw in Serbia, where Osman Bukari grabbed an 88th-minute equaliser for the home team.

Barcelona recorded a 1-0 victory away to Porto in Portugal in what was on paper their toughest assignment in Group H. Ferran Torres scored the only goal as Lamine Yamal became the youngest ever starter in a Champions League match at the age of 16 years and 83 days.

Earlier, Shakhtar Donetsk got a first win in the same group with a remarkable comeback from two goals down to beat Royal Antwerp 3-2 in Belgium.

Celtic suffered a second straight defeat in Group E after Pedro Rodriguez's 95th-minute strike gave Lazio a 2-1 victory in Glasgow.

Atletico Madrid beat Feyenoord 3-2 in the same group, with Alvaro Morata scoring twice and Antoine Griezmann also on target. (AFP)