The £60million striker opened the scoring in Sunday’s 2-1 win over Wolves at St James’ Park having replaced Callum Wilson, who had missed training through illness during the week, in the starting line-up.
His inclusion came days after head coach Eddie Howe admitted he was not yet ready to play 90 minutes on a regular basis after a lengthy lay-off with a thigh injury, but only at the intensity required by the Magpies’ front-foot approach.
Isak, 23, said: “I played almost 70 minutes, emptied myself and sometimes that’s enough. Then you’ve got fresh legs and fresh players to come in and make an impact like they did. It’s something we have in this team which is really important for us.
“I feel confident and I think I can get fitter, but I feel fit and I feel good when I’m out there and I’m not having any troubles. But I’ll just keep on working.
“The intensity is tough, but I enjoy it. I enjoy it way more like this, intense and everything goes quickly and this type of football where you have more actions for yourself as well. It’s hard work and it’s tough, but I really enjoy it.”
Isak headed the home side into a 26th-minute lead from Kieran Trippier’s free-kick minutes after keeper Nick Pope had perhaps been fortunate to escape a second red card in three appearances after colliding with striker Raul Jimenez in the box as he attempted to atone for a loose touch.
The Magpies, who had won only one of their previous eight league games to slip from third place in the table to sixth before kick-off, might have killed the game off before half-time, but didn’t and were made to pay when Hwang Hee-chan came off the Wolves bench to level.
However, fellow substitute Miguel Almiron matched his feat and his 11th goal of the season clinched a victory which eased Howe’s men back above Liverpool into fifth with a game in hand and to within four points of fourth-place Tottenham, who have played two more.
Isak said: “We’ve played well, but as everyone knows that ball hasn’t wanted to be in the back of the net, so we showed great character.”
Wolves defender Craig Dawson admitted his disappointment at the outcome on Tyneside.
Dawson told the club’s official website: “It was a tough one to take but I think we let them have too much of the game in the first half, which gives them confidence, it gave the crowd confidence.
“We’ve been in that position before and we got the goal back, so we’re obviously disappointed to concede the second goal and not to have held on in the end, but we’ve got to learn from that.”