A goal in each half gave Pompey their first league points of the season against Tranmere.
A trademark Ben Close 30 yarder lit up the match before Tom Naylor settled the home fans’ nerves 15 minutes from time.
There was a touch of Hollywood afforded the afternoon as actor and comedian Will Ferrell joined the crowd of 18,575.
Pompey were good value for the three points, but the League One new boys stayed in the game long enough and had enough threat to ensure it wasn’t comfortable for Kenny Jackett’s men.
Jackett went with an unchanged starting XI after the mid-week win over Birmingham.
Ronan Curtis fashioned the first chance after eight minutes as he ripped a 20 yarder which Scott Davies parried, before the visitors dealt with the danger.
Tranmere had their moments in the opening, though, as the bright Kieron Morris ripped a 25 yarder just wide.
The first goal arrived after 27 minutes in spectacular fashion.
Tom Naylor first saw a spectacular 20-yard volley kept out by Davies, but he was outdone moments later as Andy Cannon’s shot was blocked from a corner and Close guided in an outrageous half volley from 30 yards.
That lifted the home crowd with a spell of Pompey pressure following before Connor Jennings curled a shot into Craig MacGillivray’s arms just before the break.
Wonderful feet from Harness lit up play five minutes after the restart, but his trickery in the box ended with Anton Walkes wastefully firing over from 12 yards.
John Marquis, after being introduced for Ellis Harrison at the break, then had the ball in the net but the ref gave a foul against Tom Naylor on David Perkins.
Then Lee Brown fired wide after a flowing Blues move as they stayed on the front foot.
The post denied Pompey extending their lead in the 64th minute when Cannon hammered the woodwork in the box from Brown’s cross.
There was a let-off from the Blues three minutes later when Manny Monthe headed just wide Morris’ corner.
Pompey settled the home fans’ nerves with 15 minutes left as Naylor put daylight between the sides.
Brown’s corner was met by Downing’s head and the ball was close to being over the line, but Naylor made sure as he smashed it high into the net.
Downing was the fall guy shortly after as Pitman’s shot appeared to be on its way until it deflected off target via the defender.
Brown was denied a first Pompey goal on his 29th birthday late on after Pitman’s 20 yarder was parried by Davies, but the offside flag is up.
That mattered little, however, as the home side coasted through stoppage time to collect the points.