Adomah played a starring role as Boro beat Fulham 2-0 at Craven Cottage at the weekend.
The Ghanian winger scored Boro’s first goal of the match, before Grant Leadbitter added a second, and he was a constant threat to Fulham’s defence.
“Adomah played the same game as he did last Tuesday, and when he plays like that he’s one of the best in the league,” Karanka said.
There were doubts over Adomah’s future at Middlebsrough earlier in the month, as the 28-year-old seemed to drop totally out of contention.
Adomah was omitted from Middlesbrough’s match day squad against Leeds United, after Karanka brought in five players during the January transfer window.
However, he has reacted well to the increased pressure for places, and played key roles in Boro’s last two matches.
Adomah also stood out, as Karanka’s men picked up a 3-1 win against Cardiff City last Tuesday.
Adomah will now be hoping to retain his place in Boro’s starting line-up, as the season reaches its crunch stage.