Carolina, which has had its schedule disrupted by bad weather, won its second in a row.
Semin tied the game at 2-2 in the second period and he created a 3-3 deadlock 7:25 into the third. Sekera then gave the Hurricanes their first lead of the contest with a slap shot that rocketed past Jhonas Enroth.
Jiri Tlusty added an empty-net goal in the final second.
Carolina had a game against Philadelphia postponed earlier this week and the Hurricanes wound up winning that one on Wednesday. In order that Carolina would not have to play three nights in a row, its game against Ottawa originally scheduled for Friday has been pushed back to Saturday.
Anton Khudobin made 25 saves to get the win over the Sabres. Enroth stopped 28-of-32 shots.
Buffalo lost its fifth straight and its 13 wins are the fewest in the NHL.