The Leafs paid for a pair of second-period turnovers, as the Sabres capitalized twice in transition in the span of 1:47.
An errant pass from Nazem Kadri on the rush gave the Sabres a two-on-one that resulted in Tyler Ennis slipping a backhander past Jonas Gustavsson for a 2-0 Buffalo lead. Veteran Rob Niedermayer then took advantage of a neutral zone turnover and wired a shot past Jussi Rynnas to put the Sabres ahead 3-0.
Shots on goal favouring the Sabres on Saturday.
Goals allowed by the Leafs in six Sabres power play opportunities.
It may have been his first preseason game, but Derek Roy was in fine form on Saturday.
The veteran centre, who was a point per game player against Toronto last season, notched a pair of helpers on the Sabres' first two goals and finished with a team-best +2 rating in the win.
After a somewhat shaky debut between the pipes earlier in the week, Jussi Rynnas appeared to be heading down a similar path by quickly allowing Nidermayer's unassisted marker in the second.
But to his credit, the man known as "The Bus" stayed poised and turned away 24 Buffalo shots in just over 28 minutes of work to keep the Leafs within striking distance.
Ron Wilson had high post-game praise for the lineup of Kulmin, Grabovski and Clarke MacArthur calling them the team's only regular line on the ice on Saturday.
Kulemin led the team in shots with five, while Grabovski was tops in the faceoff circle for Toronto by winning nine draws, including one that set up Toronto's lone goal. All three players on the line finished with a +1 rating in the loss.
Ron Wilson on how his younger lineup fared against an experienced Sabres team on their home ice:
"I thought we played pretty well in the first period. Second period we didn't move the puck very well. They had us hemmed in. Some of our younger guys struggled under the kind of pressure that Buffalo can apply. Ryan Miller came up with a huge save on Clarke MacArthur and that was probably our last chance for any salvation in the game."
Monday September 27 vs. Buffalo 7 PM ET (Leafs TV, AM640)
Game Notes: The Leafs finally get a day off on Sunday after a stretch of five preseason games in five days.
The home-and-home series with the Sabres concludes on Monday at Air Canada Centre. Toronto will play in four more preseason games next week before the regular season begins on Oct. 7.