Lionel Messi struck twice as Barcelona inflicted more Champions League pain on Tottenham with a 4-2 win at Wembley, Neymar hit a brilliant hat-trick in Paris Saint-Germain's 6-1 rout of Red Star Belgrade, while Napoli snatched a 1-0 win over an outclassed Liverpool on Wednesday.
Messi's Barcelona outgun Spurs
Philippe Coutinho scored after just two minutes for Barcelona, who arrived in London winless in three La Liga matches, with Ivan Rakitic drilling in a magnificent second.
Messi, who had earlier twice hit the post, then got on the scoresheet in between goals from Harry Kane and Erik Lamela, before the Argentina superstar grabbed his second late on to seal victory.
"After a few bad results it was important to do well today. Our response was very good," said Barca coach Ernesto Valverde.
Philippe Coutinho (L) scores the opening goal for Barcelona during the Champions League Group B match at Wembley Stadium on October 3, 2018. /VCG Photo
Barca head Group B on six points alongside Inter Milan, but Mauricio Pochettino's side face a vital double-header against PSV Eindhoven after failing to collect a point from their opening two matches.
The Tottenham boss admitted Spurs had few answers for Messi as his team was left with an uphill struggle to reach the knockout stages.
"He's a fantastic player," said Pochettino. "His average performance is this type of game. He's always above everything."
Neymar bags hat-trick
PSG rebounded from their 3-2 defeat by Liverpool with an attacking masterclass against 1991 European Cup winners Red Star at the Parc des Princes.
Neymar curled in a sublime free-kick to open the scoring on 20 minutes, quickly doubling his tally before Edinson Cavani, Angel di Maria and Kylian Mbappe also found the target.
Neymar of Paris Saint-Germain celebrates his third goal during the Champions League Group C match between PSG and Red Star Belgrade on October 3, 2018. /VCG Photo
Former Germany international Marko Marin popped up with a consolation for Red Star, with Neymar completing his hat-trick from another stunning free-kick.
"I really liked the effort made by the whole team, but Neymar was sensational," said PSG coach Thomas Tuchel.
"He is one of the best players in Europe and that is very, very important for us."
Insigne sinks Liverpool
Carlo Ancelotti's Napoli top Group C on four points after Lorenzo Insigne delivered a 90th-minute winner at home to Liverpool, who are level on three alongside PSG.
Dries Mertens hit the bar for Napoli late on, but there was still time for Insigne to nick all three points at the death as he slid to poke in a cross from Jose Callejon.
"Tonight we showed this group won't just be hard for Napoli, but for everyone involved," said Ancelotti. "It means a lot to us to have won against the finalists from last year."
Napoli's Lorenzo Insigne (R) celebrates scoring a winning goal in last minute to defeat Liverpool in Champions League Group C match on October 3, 2018. /VCG Photo
"I'm not shocked. We didn't adapt, that happens," said Klopp.
"There wasn't that much pressure from Napoli, it looked like they were constantly on us but it wasn't."
"Tonight we showed this group won't just be hard for Napoli, but for everyone involved," said Ancelotti. "It means a lot to us to have won against the finalists from last year."
Antoine Griezmann scored two goals to lift Atletico Madrid, last season's Europa League winners, to a 3-1 victory over Club Brugge in Spain.
Inter, the last Italian club to win the Champions League in 2010, again recovered from a goal down to beat PSV 2-1 in the Netherlands.