EDDIE HOWE admits Newcastle United will have to continue to tread carefully with Alexander Isak as the Swede continues to build up his match fitness.

Isak was a second-half substitute last night as the Magpies claimed a 2-0 win over Leicester City to reach the semi-finals of the Carabao Cup.

The £63m summer signing from Real Sociedad played for the opening 45 minutes of Saturday’s FA Cup third-round defeat at Sheffield Wednesday, but Howe concedes he is not yet up to full speed after a lengthy injury lay-off.

Isak was sidelined for three months after sustaining a thigh injury while on international duty in September, and suffered a number of setbacks during his rehabilitation period.

Howe said: “We’re going to have to build up Alex slowly. The 45 minutes was great against Sheffield Wednesday, and today (against Leicester), he’s had a little taste again in front of the supporters, I thought he looked very sharp.”

Similarly, Howe does not yet feel Allan Saint-Maximin, who was also a second-half substitute last night, is back to his peak powers after he was laid low by an illness that affected him over the festive period.

He said: “Maxi is still feeling the effects of his illness, but he was well enough to take the field (against Leicester). I thought he did well when he came on.

“It was great to get the group together, and I include Alex and Maxi being back in that. The look of our bench looked very strong, there was a good look about the group.”