Chelsea midfielder Frank Lampard marked his record-breaking 160th consecutive Premiership appearance with a goal as the champions beat managerless Pompey.
Lampard has not missed a league match for the Blues since September 2001 and celebrated by slotting in Chelsea's second goal with a 67th minute penalty.
Hernan Crespo had put Chelsea ahead when he scored from six yards after diverting in Paulo Ferreira's shot.
Lomana Lua Lua had a shot tipped over but Pompey rarely threatened.
The match had kicked off after a tribute to George Best, who died on Friday, and fans applauded the football legend before chanting his name.
Best was a frequent visitor to Fratton Park because of his close friendship with Pompey chairman Milan Mandaric and the south-coast club's owner was close to tears during the tribute.
Pompey chairman Mandaric cut an emotional figure
Portsmouth were playing under the temporary charge of Joe Jordan after Alain Perrin's departure as manager and they started by trying to deny the champions time and space on the ball.
LuaLua's trickery up front was their main threat but Chelsea always looked comfortable against the strugglers.
The home side's failure to close down Damien Duff almost cost them a goal after the winger's 20-yard shot brought a scrambling save from keeper Jamie Ashdown.
Ashdwon's counterpart Petr Cech was also called into action and he impressively tipped over a LuaLua 22-yard strike at full stretch. But Portsmouth's resistance was then broken after 27 minutes with the poacher's goal from Crespo, who went off injured shortly afterwards.
A 12th league win of the season seemed inevitable for the Blues who had not conceded a Premiership goal in the second half this season.
That statistic rarely looked like being ended, although Portsmouth were more ambitious after the break with the vociferous crowd doing their best to raise their side.
But Pompey were left breathing a sigh of relief after an unmarked Ricardo Carvalho mistimed a header, although it was only a temporary reprieve.
Dejan Stefanovic brought down Joe Cole and Lampard sent Ashdown the wrong way as he slotted in to extend the visitors' lead.
Lampard's outing passed the previous record of 159 consecutive league appearances set by keeper David James while at Liverpool.
Portsmouth caretaker manager Joe Jordan on leaving out Laurent Robert:
"If I'm in charge for next game, I'll approach that in the same way meaning that I'll pick the team I think can get a result for Pompey.
"All the players at my disposal will be assessed and that will include Laurent Robert and everyone at the club."
Chelsea boss Jose Mourinho:
"Portsmouth had a very difficult time with Joe Cole because he played fantastic. He deserves to come out of the game as a hero and the people did not recognie the work he did.
"It was a clear penalty and he didn't deserve the reaction he got because he is a very fair player.
"I think we fought very well. The team were very intelligent in the second half the way we controlled the game and we waited for the right time to kill the game off."
Portsmouth: Ashdown, Priske, O'Brien, Stefanovic, Griffin, O'Neil, Diao, Hughes (Viafara 78), Taylor, Silva (Todorov 63), LuaLua.
Subs Not Used: Westerveld, Vukic, Vignal.
Booked: Diao, Hughes, Griffin, Stefanovic, Taylor.
Chelsea: Cech, Paulo Ferreira, Ricardo Carvalho, Terry, Gallas, Joe Cole (Geremi 83), Gudjohnsen, Essien, Lampard, Duff (Wright-Phillips 79), Crespo (Carlton Cole 38).
Subs Not Used: Cudicini, Del Horno.
Booked: Carlton Cole.
Goals: Crespo 27, Lampard 67 pen.
Ref: P Dowd (Staffordshire).