Oscar's second-half strike and Mikel's first goal in almost seven years ended a four-match winless streak and extended manager Jose Mourinho's unbeaten Premier League home record to 63 matches with a first victory since the defeat of Aston Villa.
The 2-0 win means Fulham's 34-year wait for victory at Stamford Bridge went on to the relief of Chelsea, who responded from defeats to Everton and Basle.
The visitors had chances and Chelsea, with Mourinho deeming Juan Mata not even worthy of a place on the substitutes' bench, were fortunate not to be a goal down at the interval as Darren Bent spurned the opportunity to give Fulham an early lead.
Too often the Blues relinquished possession and their attack was blunt, with Samuel Eto'o again struggling to recover former glories on his third successive start after signing from Russian side Anzhi Makhachkala.
Roman Abramovich did not appear impressed watching down from his seat, but Oscar's third of the season and Mikel's third for the club in more than 300 appearances were enough for the Blues to return to winning ways.
That Branislav Ivanovic was Chelsea's most creative player illustrated the ongoing struggle Mourinho has to overhaul their playing style.
Mourinho insists he will accept short-term pain for long-term gain, but admitted positive results were required early in the Blues' "beautiful project".
After two "ugly" results - the recent defeats, which followed a draw at Manchester United and a European Super Cup penalty shootout loss to Bayern Munich - this was far from pretty.
Mourinho left out Mata and David Luiz, both of whom sat behind the bench having failed to satisfy their manager's tactical demands.
In the first half, it looked like Chelsea could have done with them, Mata for his guile and Luiz for his ability to play a defence-splitting pass.
Four changes were made following Wednesday's shock Champions League Group E loss to Basle, with John Terry, Mikel, Ramires and Andre Schurrle brought in.
Martin Jol, who was the subject of jeers following last Saturday's 1-1 draw with West Brom which extended Fulham's wait for a home to six matches, made three changes and fielded three former Blues.
Two combined early on when Damien Duff crossed for Steve Sidwell, who mistimed his leap.
Eto'o, profligate in the loss at Everton and anonymous against Basle, next had an opportunity to put the Blues in front but David Stockdale did just enough to deflect Ivanovic's cross away at the near post.
Schurrle, nominally starting in Mata's place on the right wing with Mourinho preferring Oscar as his number 10, kicked thin air when an Ivanovic cross was played towards him at waist height before Fulham had the chance of the half.
Bent was played through by Pajtim Kasami and had enough pace to surge clear, but Petr Cech held his weak shot. It was a fluffed chance which illustrated the on-loan Aston Villa striker is still to find form after a number of niggles this term, yet still Terry appeared ruffled every time Bent was lurking.
Chelsea had numerous opportunities themselves but did not test Stockdale, with Fulham time and again getting in crucial blocks.
Having performed well in the first period, Stockdale was culpable for the opening goal.
Schurrle cut in from the left and fired right-footed straight at the Fulham goalkeeper, who failed to hold the ball, allowing Eto'o to follow up.
The Cameroon striker's effort was blocked by Stockdale, but Oscar bundled the ball in via a deflection as the Brazil forward extended his fine start to a campaign.
Moments later, Fulham should have levelled but Sidwell, unmarked at the far post with Chelsea's defenders occupied by Brede Hangeland, headed Kasami's free-kick wide.
Eto'o was replaced by Fernando Torres and Duff by Adel Taarabt as their respective managers sought a spark, but few would have guessed the next scorer.
Stockdale made a fine reaction save to deny Torres from Oscar's corner, resulting in another set-piece.
And Lampard's cross was headed down by Terry for Mikel to scissor-kick the ball in.
The Nigeria midfielder's previous goals were in successive FA Cup rounds in January 2007 against Macclesfield and Nottingham Forest and in the remaining minutes Mikel was urged to shoot by the Stamford Bridge faithful, even when in his more customary position protecting the back four.