London, Dec 2 : Champions League winner Chelsea squeezed past Watford 2-1 to maintain their slender lead at the top of the Premier League on Wednesday night. Close rivals Manchester City, the defending champions, and Liverpool too won their respective matches to remain on the heels of the Blues after the mid-week fixtures. Mason Mount was decisive for the league leaders, scoring the 29th-minute opener and then setting up Hakim Ziyech for the winner after Watford had equalised from Bonaventure' deflected 43rd-minute shot. The game was halted for half an hour in the first half for a medical emergency and Watford later confirmed a fan was in a stable condition after suffering a cardiac arrest while in the stands. According to reports, the players agreed to resume play only once they were sure the situation had taken a positive turn. The supporter was stabilised before being taken to the hospital, with medics from both clubs contributing to his treatment. Meanwhile, things went smoothly for defending champions Manchester City. Ruben Dias scored a goal with a left-foot shot to open the scoring for City away to Aston Villa in the 27th minute and Bernardo Silva made it 2-0 shortly before halftime. Ollie Watkins pulled a goal back for Aston Villa early in the second half, but Manchester City inflicted Steven Gerrard's first defeat as Villa coach on the day City midfielder Jack Grealish was booed as he faced his former club for the first time since leaving this summer. At Goodison Park, Liverpool got off to a flying start in their 4-1 derby win away to Everton with Jordan Henderson and Mohamed Salah putting them 2-0 up within 19 minutes, with Henderson netting a first-time finish and Salah curing the ball past Everton keeper Jordan Pickford. Demarai Gray pulled a goal back for Everton in the 38th minute after a pass from Richarlison, but Salah's second of the game in the 69th minute again put Liverpool two goals clear and Diogo Jota netted the Reds' fourth in the 79th minute to pile the pressure on former coach Rafael Benitez. With the latest win, Chelsea moved to 33 points from 14 matches with City at 32 and Liverpool a further point behind. Neal Maupay's 89th-minute goal saved a point for Brighton on their visit to West Ham, who had taken a fifth-minute lead through Tomas Soucek. Burnley continue to collect points and extended their unbeaten run to five games with another solid defensive display to earn a 0-0 draw away to Wolves, although they remain in the bottom three. Southampton and Leicester City shared four goals with Southampton twice taking the lead through Jan Bednarek and Che Adams only to be pegged back by Jony Evans and James Maddison. /IANS