Josh Murphy (left) scored his fifth goal - and second against Swansea - since joining Portsmouth last summer
Portsmouth climbed out of the Championship's bottom three thanks to a thumping victory over Swansea City.
Josh Murphy's crisp first-time finish gave the hosts a 22th-minute lead, before Paddy Lane poked home the second seven minutes later.
Swansea briefly threatened to mount a comeback after the break, with Josh Tymon going closest when he rattled the woodwork, but Ryley Towler's header eased any Portsmouth nerves and Cyrus Christie's error allowed Colby Bishop to wrap up a comprehensive win.
While John Mousinho's team have struggled on the road this season, a sharp upturn in home form has breathed life into their bid to avoid an immediate return to League One.
Portsmouth have now collected 13 points from the past five games on their ground and scored 14 goals in the process.
But it was a dreadful afternoon in the Fratton Park rain for Swansea, who slip to 12th after some hapless defending contributed to their heaviest defeat of the season.
Portsmouth are a point clear of the relegation zone in 21st.
These two sides drew in south Wales just over a month ago, when Swansea came back from 2-0 down to claim a point having been troubled by Portsmouth's high press.
The same approach paid dividends once more for Pompey – and this time Luke Williams' team could not muster a response.
It was Portsmouth's refusal to allow Swansea to settle in possession which brought the opening goal, the home side striking after Zak Swanson dispossessed Liam Cullen near halfway.
After a swift exchange of passes with Lane, Swanson's whipped cross allowed Murphy to steer the ball high into Lawrence Vigouroux's net.
Portsmouth kept on pressing, and Swansea continued to wobble.
The second goal came after a Vigouroux pass was intercepted, with Harry Darling's attempted clearance headed back into the penalty area by Connor Ogilvie.
Amid indecision in the Swansea defence, Tymon's weak header allowed Lane to poke in his first goal of the season.
Only then did Swansea begin to turn their control of possession into an attacking threat, with Eom Ji-Sung denied by Swanson's recovery challenge before Cullen headed over.
Swansea's best chance of the half came just before the break, when Florian Bianchini headed too close to Portsmouth keeper Nicolas Schmid with the goal at his mercy.
Colby Bishop's goal was his third since he returned to action in November after heart surgery
There were further opportunities as Swansea applied pressure early in the second period, with Eom denied by a sharp Schmid save, before the South Korean's reverse pass saw Tymon smash a shot from a tight angle against the bar.
Yet any home concerns were eased after Jay Fulton's foul on Bishop gave away a cheap free-kick.
Freddie Potts delivered from the left and Towler brushed off the attentions of Eom to beat Vigouroux from eight yards.
The Swansea stopper then denied Callum Lang and Murphy, before Bianchini found the Portsmouth net with a header only to be flagged offside.
There was more misery to come for Swansea 12 minutes from time, as substitute Christie miscontrolled in his own area and Murphy squared for Bishop to score from close range.
Portsmouth head coach John Mousinho:
"A brilliant win. Great to get a clean sheet, great to score four goals and the performance backed it up against what I think is a really, really good side.
"Swansea can cause you all sorts of problems and sometimes you do have to ride your luck. At 2-0 we were a bit fortunate not to concede a goal, but at the same time we had plenty of chances in the first half.
"Against Swansea, I think they are the best side in the league for possession, maybe apart from Leeds. They are fantastic the way they dominate the ball, the way they rotate.
"But I thought we dealt with that really well. I think three of the four goals are from the way that we press, then we got the set-piece as well."
Swansea head coach Luke Williams:
"We struggled to get to grips with the conditions and the opposition were excellent.
"It was a very bad day at the office. If we want to be a better team then we have to find a level of consistency.
"The last two performances before this were excellent.
"That's the type of team we want to be week in, week out and that's what we are building towards."
