Liverpool have moved 11 points clear at the top of the table with victory over Brighton.
The Reds were coasting to victory after two Virgil van Dijk headers from Trent Alexander-Arnold assists in the space of six minutes during first half.
But Alisson's red card - for clearly handling outside his penalty area with Brighton substitute Leandro Trossard bearing down on goal - gifted Brighton a lifeline.
Earlier in the day, reigning champions Manchester City were held to a 2-2 draw at Newcastle United.
Meanwhile Tottenham Hotspur made it three wins out of three under manager Jose Mourinho, against a Bournemouth.
The result move Tottenham, who secured their first back-to-back Premier League victories this season, up to fifth in the table, while the visitors drop to 12th.
Elsewhere West Ham relieved the pressure on boss Manuel Pellegrini as they ended their seven-game winless run with a first victory at Chelsea for 17 years.
Lastly Crystal Palace earned their first Premier League win in six games in a cagey affair at Burnley.
Premier League Results:
Newcastle United 2 Manchester City 2.
Burnley 0 Crystal Palace 2.
Chelsea 0 West Ham 1.
Liverpool 2 Brighton 1.
Tottenham 3 Bournemouth 2.