Bolton are winning games the hard way at the moment, but a fifth successive victory consolidated their top-four place at the expense of one of their main challengers.
Wanderers are making a habit of giving sides a start, but they got away with it again as goals from Abdoulaye Faye, Ivan Campo and Nicolas Anelka, with his seventh in eight games, wiped out the early one they conceded to Matthew Taylor. Andrew Cole's late effort made it a nervous last few minutes for Bolton, but apart from the beginning and end they dominated a game of commendable quality considering the wretched conditions.
"It was two teams at the top level justifying the positions they're in on a very difficult surface," said the Bolton manager, Sam Allardyce, who admitted to "huge satisfaction" at the way his team came back from their early deficit. "It shows great character as well as great ability and strength."
Bolton had to show those qualities again after starting even more slowly than they did against Newcastle on Boxing Day. Cole, leading the attack in the absence of the rested Nwankwo Kanu, caught them out after just one minute and 40 seconds, flicking the ball on for Taylor to beat Faye's lunge and put it beyond Jussi Jaaskelainen. It was Taylor's sixth goal of the season, a remarkable return from a converted full-back and one of the reasons why Pompey are as high in the Premiership table as they are.
Bolton's response, though, was an outstanding illustration of why they are allowing themselves to think of Champions' League qualification. A combination of the incisive running of Anelka and the sheer industry of Kevin Davies forced Portsmouth on to the back foot and Wanderers were level on the half-hour.
A promising build-up between Anelka and Abdoulaye Meite earned a corner, which was put over by Gary Speed from the right. The Portsmouth goalkeeper, David James, could not claim it and Faye's header was on its way in when Gary O'Neil's effort on the line helped it into the roof of the net.
Ten minutes later, Bolton were ahead. Anelka had been worrying Portsmouth with his control and acceleration, but the goal came from the direct route when Tal Ben Haim found Davies's head only for James to deny him with a flying save. Unfortunately, for a goalkeeper not having the happiest afternoon of an outstanding season Campo was following up and there was no keeping the second header out of the net.
Jaaskelainen protected that lead with a fine save at Cole's feet before half-time, and James did the same to Kevin Nolan early in the second half after Davies had put his captain clean through. Bolton's in-form Finnish goalkeeper then got his legs in the way to defy Cole again as Portsmouth continued to look dangerous.
Bolton took a winning lead, however, just after the hour mark when Davies, who was chasing everything, got in a low cross from the left and a deflection from Sol Campbell contributed to James being unable to hold the ball. There was Anelka, lurking to continue his prolific scoring streak much to the frustration of the Portsmouth manager, Harry Redknapp, who admitted to having tried to sign him last summer.
That was not quite the end of the drama, because Cole scored with a long-range shot with 90 seconds to play plus a generous four minutes of added time which Bolton successfully played out as they underlined their top-four credentials.