Portsmouth completed their third away win of the season, seeing off a spirited challenge by under-strength Gillingham with Paul Merson again catching the eye.
The 34-year-old former England midfielder made another outstanding contribution to the game, scoring one and creating another for substitute Gary O'Neil.
"It was pleasing to get another three points away from home but I thought Gillingham manager Andy Hessenthaler was outstanding for them," said Pompey boss Harry Redknapp after the match.
"He never gave up and he ran all afternoon."
Hessenthaler admitted: "I'm not too disappointed bearing in mind all our injuries.
"We had a settled side for the first three games but injuries have disrupted us.
"Tommy Johnson had to come off and will be out for between two and four weeks with a hamstring injury. We can't keep harping on about it. We've just got to get on with it starting at Torquay in the Worthington Cup on Tuesday."
Pompey started well and could have taken the lead twice in the first 15 minutes. Merson sent a curling 30-yard effort wide and then set up Mark Burchill but his left-foot shot went just past the post.
Gillingham then had a good spell and Paul Shaw saw his fierce effort tipped against the bar by Shaka Hislop.
Portsmouth broke the deadlock on the half hour. Matthew Taylor's cross caught the Gillingham defence in two minds and the ball fell to Merson who side footed home from 12 yards out.
Had Gillingham got the break trailing only 2-1 they would not have been too disappointed only for Burchill to make it 2-0 on the stroke of half time.
Mark Patterson and goalkeeper Vince Bartram got in a mix-up and Burchill had the simple task of scoring into an empty net.
Gillingham kept at it and got themselves back into the game in the 67th minute when substitute Kevin James headed in Mark Saunders' cross.
Gillingham missed a great chance to make it 2-2 when Linvoy Primus cleared off the line under pressure from James, an early replacement for the injured Johnson.
Portsmouth made a couple of changes sending on Kevin Harper and O'Neil and it was the latter who scored the third, set up by Merson with 11 minutes left