Teemu Pukki has scored in his last three games for club and country
Middlesbrough suffered their first Championship defeat of the season and conceded their first league goal since the opening day as Norwich prevailed at Carrow Road.
The hosts had the better of a low-key first half but Boro had the best chance as Jonny Howson's turn and shot was well stopped by Canaries keeper Tim Krul.
Norwich took a deserved lead when Emi Buendia teed up Finland striker Teemu Pukki to poke in his fourth goal in five home games for the club.
Boro boss Tony Pulis brought on George Saville for his debut but the visitors were unable to find a way past Dutchman Krul, who saved superbly from fellow sub Martin Brathwaite.
Victory gave Daniel Farke's Norwich just their second league triumph of the season, while Middlesbrough fell from second to fourth in the table after this maiden loss.
The Canaries were without captain Grant Hanley through injury but shut out their opponents and ended their run of five league clean sheets in a row, becoming the first team to score a second-half goal against Boro this term.
Summer signing Pukki continued his scoring streak, having netted winners in both of Finland's Nations League games over the international break.
Norwich - who have now alternated between a win and a defeat in their last nine home Championship games - have won their last four matches against Middlesbrough in all competitions without conceding.
Norwich boss Daniel Farke said:
"It was a brilliant performance, we controlled the game, dominated possession and I think when we got the goal it was well deserved.
"We were up against a very strong side, who are near the top of the table and had just kept five successive clean sheets. They are a big, strong side and it was important we had a plan to deal with them.
"When you stick to a plan well then this is the result. We brought our football onto the pitch - and got what we deserved."
Middlesbrough manager Tony Pulis said:
"It's disappointing, I thought we had a pretty good start.
"A couple of opportunities, a couple of chances, an array of corners and we dropped off after about 20 minutes and they came into the game, and they were the better team up until half-time and they were better after the break as well up until they got the goal.
"From there they get their goal and it's a fortuitous goal, it's going wide, the lad toe pokes it, hits Ryan Shotton on the inside of his foot and goes in. Not our day in lots of respects."
