Lee Brown believes that Pompey have got the best defence in League One.
But the left-back knows they cannot rest on their laurels after beating Coventry to remain top of the table.
A clean sheet at the Ricoh Arena ensured Ronan Curtis’ strike on the stroke of half-time was enough to secure all three points.
And with Barnsley and Blackpool the only third tier sides to have conceded fewer goals this term, Brown knows it is a key factor in their success.
He said: “I think that’s been the catalyst for the whole season so far and it’s something that the manager’s big on.
“We said at half-time that we need to stay switched on because their only chance had come from our mistake.
"The boys at the front need to have faith that if they score one goal, we can keep a clean sheet at the other end."
“It’s vital for any team that wants to do well to be built on solid foundations and we’ve got a really strong base.
“The boys at the front need to have faith that if they score one goal, we can keep a clean sheet at the other end.
“But we can’t take anything for granted and even though I believe we’ve got the best defence, it can easily change.
“I still think there’s room for improvement and we all know there’s another few gears that we can find, which is a positive.”
Their latest victory means that Pompey have now gone an incredible 11 league fixtures without tasting defeat.
Brown said: “That spirit wasn’t necessarily there when I first came here, but I think it’s definitely there now. That only comes from winning games together.
“We won’t get carried away. I know the fans are enjoying it – and rightly so – but in the dressing room it’s just a case of on to the next game.
“Every team now will want to take this crown from us and be the first team to beat us, so we’ve got to keep doing what we’ve been doing.”