Boss felt Blues were patchy despite beating Luton
Paul Cook brought on Matt Tubbs and Conor Chaplin for the closing stages at Kenilworth Road.
And the double switch worked a treat as the duo combined to grab Pompey a late, late winner against Luton.
They had earlier seen Gareth Evans’ first half opener cancelled out by a Craig Mackail-Smith penalty.
But, with a draw looking likely, Chaplin raced onto a long ball and when his shot was saved, Tubbs followed up to score.
It was a result that ensured Pompey continued their impressive start to the season, although Cook felt they were slightly fortunate claim all three points.
The Blues boss said: “We’d taken control of a difficult away game and scored a good goal, but then we got sloppy.
“We weren’t happy at half-time because the equaliser had allowed them to get into the ascendency.
“Once we got to 80 minutes we thought ‘why not have a go’ because we’re still unbeaten away from home.
“Conor came on and affected the game, which was pleasing, while Tubbsy did his job by getting us the goal.
“Crawley was a game that we should have won, but didn’t, while we won a game this time that probably should have been a draw.
“It was a bit of a mixed bag in terms of how we performed – there were glimpses of quality, but we were lacklustre at times.
“We’re really pleased to get all three points, however, and now we just move on to the next game.”
Cook is now looking forward to back-to-back Fratton clashes with Accrington and Barnet.
He said: “We’ve got a squad that has momentum and belief and after our Johnstone’s Paint Trophy match in midweek, we’re pleased to have two home games in front of our fans.”
See what Cook had to say below or subscribe to Pompey PlayerHD for full interviews with the manager and Matt Tubbs.