AC Milan and Inter Milan have backed out of the breakaway competition, leaving Juventus as the only Italian club persisting with the plans. "The rules are clear.
Mohamed Salah had given the hosts the lead in the first half with a deflected strike, before Heung-min Son levelled with a breakaway goal. After the break, Spurs missed several chances to take the lead, before Firmino struck.
Of the 12 teams to form the new breakaway league, only Barcelona, Real Madrid and Juventus are still on board. The other nine signed a letter of apology to UEFA and pledged to donate £12.9m to grassroots football.
The Spanish giants, led by president Florentino Perez, were at the forefront to form a breakaway competition. The project was eventually shelved within 48 hours of coming into existence.
"Maybe they overthought things whereas if us and City both won it made them think, 'we need to just win' rather than it being a chance to breakaway from the pack.
Manchester United, Manchester City, Liverpool, Arsenal, Chelsea and Tottenham all pulled out of the controversial breakaway plans within days of them being announced, Their decision came after outrage from across the football world.
David Luiz also hit a post with a free-kick and Moses forced an excellent save from Schmeichel when the outstanding N'Golo Kante led a swift breakaway.
Chelsea, Tottenham, Manchester United, Manchester City, Arsenal and Liverpool have all signed up as founding members of the new breakaway league alongside Spanish topsides, Atletico Madrid, Real Madrid, Barcelona and Italian giants Juventus,
The trio are the only clubs left of the initial 12 that were involved in the breakaway plans. The nine clubs who pulled out, all signed the Club Commitment Declaration with UEFA on Friday.
Chelsea, Arsenal, Liverpool, Manchester United, Manchester City and Tottenham announced their withdrawals from the breakaway league following widespread backlash from fans, football figures and politicians across Europe.
The six clubs - Arsenal, Manchester United, Chelsea, Liverpool, Tottenham Hotspur and Manchester City - have signed a UEFA 'club commitment declaration' after backing down in their breakaway bid.
Real and Chelsea were both part of the 12 big clubs, who announced their intention to form a breakaway competition on Sunday night. It has now collapsed following protests from fans, players, managers and pundits.
The visitors secured the three points in stoppage time as another breakaway move saw Mo Salah feed Sadio Mane, who rounded Wayne Hennessey to wrap up the fixture.