Dan Gosling was Bournemouth's hero six minutes from time as Chelsea suffered a poor Premier League home defeat at Stamford Bridge.
Frank Lampard's side secured their place in the last 16 of the Champions League with victory over Lille in midweek, but The Blues have now lost four of their last five games in the Premier League.
Lampard made three changes to the side that lost 3-1 at Everton but once again they lacked spark and invention.
Mason Mount was presented with a great opportunity following a beautiful pass by Jorginho but was denied by Aaron Ramsdale in the only chance of note in the first half.
Chelsea's results and performances at Stamford Bridge under Lampard has been largely underwhelming and he couldn't inspire his men to an improved second-half performance, creating little and again looking nervy at the back.
The game was won six minutes before the end when Chelsea failed to clear from a corner, the ball was headed into the path of Gosling who flicked the ball over the head of Kepa Arrizabalaga. After a lengthy VAR check, the goal was awarded, with Mason Mount playing the Bournemouth midfielder onside.
Aaron Ramsdale saved from Mateo Kovacic's volley as Chelsea piled the pressure on for an equaliser, but the Cherries held on to register a fine victory and end a sequence of five straight defeats.
The result allowed fifth-placed Sheffield United to close the gap on Chelsea to four points and Manchester United could move within two points if they beat Everton at Old Trafford on Sunday. Meanwhile, Eddie Howe's charges jump up to 14th, four points above the drop zone.
Chelsea's home blues continue. Frank Lampard was given a huge boost this week with the news that the club can make signings in January and it is clear that he needs reinforcements. The development of several young players has been a huge source of encouragement this season, but if Chelsea have genuine top four aspirations, they need established quality players. Chelsea have only won five games in all competitions at home this season, taking 14 points in the Premier League at their home, dropping points to teams they ought to be beating. Bournemouth had come here after five straight defeats and with only one win in 10, they really shouldn't be taking maximum points at Stamford Bridge. January cannot come soon enough for Lampard, who needs another defender and more firepower.
MAN OF THE MATCH
Aaron Ramsdale (Bournemouth): The travelling supporters sang 'Ramsdale for England' and this was a performance that would have impressed Gareth Southgate. A calming influence, Ramsdale had his defence expertly organised and he made two excellent saves to ensure his team kept a clean sheet.
Chelsea: Kepa 6, Emerson 6, Rudiger 7, Zouma 8, Azpilicueta 6, Jorginho 7, Kante 6, Willian 7, Mount 5, Pulisic 5, Abraham 5.. subs: Hudson-Odoi 4, Kovacic 5, Batshuayi 4, James.
Bournemouth: Ramsdale 8, Stacey 7, Francis 7, Mepham 6, Rico 7, Fraser 8, Lerma 7, Billing 7, L Cook 7, Gosling 8, King 8.. subs: Solanke 4.
8' - Chance for Mount! Oh what a beautiful pass from Jorginho. His first-time lobbed ball picks out Mount, who is through one-on-one with the goalkeeper but Ramsdale dives at his feet to make a brave save.
66' - So close! Oh, how close do Bournemouth go to taking the lead?! Hudson-Odoi misplaces a pass, King pounces and he races down the left, squares it for Gosling but he can't make the connection, even at full-stretch! He was inches away from a tap-in.
73' - Point-blank save! Chelsea squander their best chance of the game! Head tennis in the Bournemouth penalty area, the ball comes to Emerson who has a chance to open the scoring from point-blank range but he nods it straight at Ramsdale.
84' - GOAL! - Chelsea 0-1 Bournemouth (Gosling): Chelsea fail to clear a corner,, Gosling lifts the ball over the head of Kepa and after a VAR check that takes a couple of minutes, the goal is given! Mount was playing the Bournemouth midfielder onside!
- Since they were promoted to the Premier League in 2015, no side has won more away league games at Stamford Bridge than Bournemouth.
- Chelsea have lost three of their nine Premier League home games this season, more than twice as many as in the entirety of 2018-19.
Dan Gosling of AFC Bournemouth scores his team's first goal which is given following a VAR check during the Premier League match between Chelsea FC and AFC Bournemouth at Stamford Bridge on December 14, 2019 in London, United Kingdom.
Image credit: Getty Images