Going into the October international break without a win after seven Premier League games, nine including the end of last season.
Trevoh Chalobah put the hosts ahead after nine minutes, swooping at the back post to head in his second of the season after Ruben Loftus-Cheek flicked on Chilwell's corner.
A dominant Chelsea had the ball in the net on two further occasions in the first half, however Romelu Lukaku was flagged offside and Werner's header was ruled out following a foul by Cesar Azpilicueta on Kyle Walker-Peters in the build-up.
The hosts were punished for not extending their advantage when former Chelsea player Tino Livramento was tripped by Chilwell in the box and Ward-Prowse fired in the resulting penalty.
However, we could not hold out for a point following the loss of their skipper, whose yellow card was upgraded to a straight red after referee Martin Atkinson viewed the pitchside monitor. Goals from Werner and Chillwell killed the game.