Connor Ogilvie was delighted with the first half performance that earned Pompey all three points at Barnsley to take them to the League One summit.
The defender headed home a fine Joe Morrell cross to put the visitors three goals up inside the opening 16 minutes.
That came after Colby Bishop’s early Oakwell penalty was immediately followed by a strike from Paddy Lane.
The home side pulled two back after the interval to ensure a nervy finale, but the mountain proved impossible to scale.
Ogilvie said: “It was probably a game of two halves. The first half is the best we’ve been and then they make some changes and it’s completely different.
“We put Barnsley under pressure, didn’t give them any time on the ball and then took our chances when they came.
"We were well beaten here last season, but now we’ve beaten them and the work in the first half meant it was warranted."
“Joe put it on a plate for me and I was only a few yards out – I just wanted to make sure I got enough power on the header and hit the target.
“Going in 3-0 up at the break sets you up to win the game, but we were facing a good team and they weren’t just going to roll over.
“Thankfully, we were able to hold on to get the win, which shows the character we’ve got in this group.
“We were well beaten here last season, but now we’ve beaten them and the work in the first half meant it was warranted.
“It’s nice that we’re top of the league, but we won’t be getting carried away because there’s a long way to go.”
Ogilvie limped off the pitch midway through the second half, with Jack Sparkes completing the match at left-back.
He said: “I just felt my groin a little bit, so we’ll assess that over the next few days and go from there, but fingers crossed it’s not too serious.”