The defender is confident the Blues can reverse their worrying form after losing more ground in the race for the Championship.
But Thompson warned his team-mates they have to eradicate the sloppy errors which are proving so costly, as they made it four league wins without victory.
Pompey were active in the transfer window, seeing six players arrive and five depart.
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With the likes of Oli Hawkins and James Vaughan on the bench on Saturday, and Brett Pitman not in the squad, Thompson feels the talent is there to turn the corner.
He said: ‘I think we do need to be patient. That’s difficult, though, because the first half of the season galvanised everyone.
‘We were riding a crest of a wave and there was a real sense of confidence around the place.
‘Naturally when you go four games without a win it can deflate everyone.
‘But as soon as we pick up three points again that feeling will come back.
‘So, hopefully, we can turn the corner.
‘We’ve bought players and we’ve got strength in depth now.
‘When you see the calibre of players coming off the bench now, you can see there is real competition for places. That can only be a good thing.
‘It's tough, though. You only have to look at the Premier League and the likes of Manchester City and Liverpool dropping results when they were flying.
‘Football is like that, and that is why people lose accumulators every week!
‘It’s important we get back to how we were in the first half of the season and start getting the small details right again.
‘We’ve stopped doing that slightly and started resting on our laurels.
‘If we start doing that again the results will follow.'
Thompson was unhappy with the manner in which Mallik Wilks’ first-half finish was conceded as Christian Burgess was caught out seconds after coming on for Jack Whatmough.
There also appeared to be some hesitancy from Craig MacGillivray, but it was the manner the goal game from a Pompey free-kick which really irked the 28-year-old.
Thompson added: ‘It’s things like set-pieces. Their first goal came from our free-kick.
‘We’ve switched off and not locked off the edge of the area, and that allowed them the chance.
‘It’s difficult to take, because we weren’t doing that over the first half of the season.
‘Those opportunities were being given, so we need to get back to basics over that and get it right again.
‘We looked at the goal again and there was an argument for Craig coming and staying.
‘Basically we don’t organise and there’s hesitation in terms of Christian going and they’ve got two men forward.
‘Whatever, it’s sloppy from us and a team near the top shouldn’t be conceding goals like that. It’s not good enough.’