Buendia struck with a superb volley after 62 minutes at Carrow Road to give Daniel Farke's team its first victory in three matches.
Norwich, relegated from the top-flight last term, is now four points clear of second placed Swansea City.
Jamal Lowe struck twice as Swansea came from behind for a 2-1 win over sixth placed Watford at Liberty Stadium.
Tom Cleverley gave Watford a 20th minute lead, but Lowe levelled before the break and then headed home from Korey Smith's cross midway through the second half.
Bournemouth is in third place after grabbing a late win in a tight tussle with Stoke City.
Junior Stanislas scored the only goal of the game, collecting a long ball over the top of the Potters' defence to slot home in the 79th minute.
Lucas Joao bagged a brace as he made an impressive return from injury in fourth placed Reading's 2-1 win at Huddersfield Town.
Fraizer Campbell gave the Terriers an early lead at John Smith's Stadium, but Joao equalised seven minutes after the break.
Campbell settled the contest with a superb turn and long-range strike 13 minutes later.
Wycombe Wanderers remains bottom of the table after surrendering the lead to lose 3-1 at home to Middlesbrough.
Uche Ikpeazu scored his first goal for the Chairboys after three minutes but Marcus Browne and Marcus Tavernier responded.
Tavernier later hit the frame of the goal but Chuba Akpom put the result beyond doubt after a corner nine minutes from time.
Millwall's poor home form continued as it lost 2-1 with 10 men to Coventry City at The Den.
The Lions fell behind when Jake Cooper turned into his own net after 20 minutes and Gustavo Hamer added Coventry's second six minutes later.
Jed Wallace pulled one back from the penalty spot after 74 minutes but it was not enough for Millwall, which had Murray Wallace sent off late on as its winless home run extended to eight games.
Bradley Dack scored his first goal for over a year as Blackburn Rovers won 2-0 at Birmingham City.
Lewis Grabban scored a 70th-minute penalty as Nottingham Forest won 1-0 at Preston North End, while Rotherham United's clash with Cardiff City was postponed an hour before kick-off after heavy snow in South Yorkshire.