Kenny Jackett explianed why he made just one substitution at Bristol Rovers.
Ellis Harrison was the only change the Pompey boss introduced during the 2-2 draw at the Memorial Stadium on Saturday.
The summer signing from Ipswich replaced John Marquis in the 91st minute.
However, it wouldn't prevent the Gas from netting an equaliser two minutes later which arrived via a bizarre Craig MacGillivray own goal from a corner.
Some sections of supporters felt fresh legs should have been brought on earlier in the game and Jackett should have used his full quota of subs.
But the boss revealed his reasons.
He said: ‘I tried to slow the game down a bit and give us a bit of a breather if we could.
‘I subbed a centre-forward to give the boys at the back a bit of a breather really.
‘They were doing all right. I obviously didn’t use my subs but I did think the lads were doing all right.
‘Towards the end, you just obviously want to slow things down slightly if you can and stop the momentum, the crowd and the opposition if possible.
‘That’s where the sub was, although I don’t think he really had long enough or any decisive incidents to affect the opposition.’
Pompey dropped points in stoppage-time for successive weekends, after conceding a late, late goal to lose 1-0 to AFC Wimbledon.
The Blues were heading for victory after Gareth Evans’ penalty and Ronan Curtis’ header either side of half-time put the visitors in the driving seat.
Jackett’s previously been satisfied with a draw at Rovers in his managerial career.
But he didn’t feel that way on his most recent trip to the Memorial Stadium.
He added: ‘The last two Saturdays we have conceded an injury-time goal that both directly affected the result.
‘It’s not as if you're 2-0, 3-0 or 3-1 up – both have resulted in a swing.
‘We were in a very good position. I don’t feel like it’s a point earned.
‘I have been here many times and earned a point. We do feel there were three points there and haven’t got them.’