Kenny Jackett felt his half-time substitutions gave Pompey much-needed impetus against Coventry.
The boss opted for a double switch during the interval of yesterday’s 2-1 victory over the Sky Blues at Fratton Park.
Trailing 1-0 at the break, courtesy of Jordy Hiwula’s ninth-minute opener, Jackett introduced Ronan Curtis and James Vaughan for Gareth Evans and Oli Hawkins.
The hosts were much improved in the second period and fought back to deliver a seventh straight League One victory and stay firmly in the automatic promotion race.
Vaughan proved a handful up front, while Curtis' cross led to Brett Pitman’s match-winner in the 83rd minute.
Tom Naylor had equalised for Pompey midway in the 66th minute.
Jackett admitted his side struggled to get a real foothold in the game during the opening 45 minutes.
But he felt his intervention changed the dynamic of the clash.
The manager said: ‘I didn’t think it wasn’t quite going for us, particularly going forward.
‘We needed to change the dynamic slightly and the focus.
‘For James, his contribution was vital in the second half. His hold-up play, some of his lay-offs and generally some of his talking and decisions were generally very good.
‘I was very impressed with him.
‘For Ronan, we all know what a good player he is and how he can produce in key moments that can get you back into a game.
‘His pace, strength and ability is obviously a threat going forward.’
Hawkins was starved of service in the first half and was rarely able to put the Coventry defence under significant pressure.
Jackett thought a change of personnel would not only re-energise Pompey but also the Fratton faithful.
He added: ‘It may have been harsh because Oli has been a good player for us.
‘But James’ experience gave us something different.
‘The fact we were 1-0 down, the thought was it could slightly re-energise our team slightly and give the crowd a bit of focus and optimism going into the second period.’