Chelsea boss Guus Hiddink says Portsmouth are capable of beating anyone in the league.
Hiddink maintains Chelsea will not be complacent at Fratton Park tonight.
"Portsmouth can test anyone, and Chelsea especially," he said.
"The clubs now who are fighting to avoid relegation, they are strong and they see every week that they have to gather the points, as Stoke did yesterday.
"That is difficult because the teams at the bottom have this specific English commitment.
"In other leagues, if you are second and play the teams at the bottom, it is not easy but it is easier than here. That is why they will give us a big challenge tomorrow."