Rolston, who until Wednesday was the head coach of the AHL's Rochester Americans, was named the Sabres interim coach following the club's stunning decision to fire Lindy Ruff.
Ruff, who had played 10 seasons for Buffalo, had been behind the club's bench since 1997 and was the NHL's longest-tenured head coach.
But the Sabres (6-11-1), who have dropped three straight and 5-of-6, were booed off the ice following Tuesday's 2-1 home loss to Winnipeg. They dropped to 9-6-1 in the first game of a new head coach, to the delight of an Air Canada Centre gathering of 19,473 that included newly crowned NBA slam-dunk champion Terrence Ross of the Toronto Raptors.
Van Riemsdyk's power-play goal at 14:28 of the third — his team-leading 11th — gave Toronto some much-needed breathing room after Buffalo goalie Ryan Miller stoned Van Riemsdyk with a fabulous glove save earlier on the power play.
Dion Phaneuf had the other goal Toronto (11-7-0), which won its third straight home game to improve to 4-4-0 at Air Canada Centre. Ben Scrivens stopped 29 shots for his third win in five starts since incumbent James Reimer's knee injury Feb. 11.
Tyler Ennis scored for Buffalo, which dropped to 3-6-0 on the road.
Buffalo outshot Toronto 12-10 in an entertaining first and also had the period's lone goal. Ennis registered his sixth of the season with high wrist shot to Scrivens' blocker side at 13:20. Both goaltenders were sharp as Miller made a fabulous save off Toronto's Leo Komarov while Scrivens twice denied Thomas Vanek with a nice split-pad save.
Phaneuf's one-timer with four seconds remaining on a power play at 1:15 of the second tied it. The goal was the 100th of Phaneuf's NHL career. Buffalo's Steve Ott put a backhander past Scrivens at 7:08 but it was disallowed because of a goalie interference penalty on Kevin Porter.
Van Riemsdyk then put Toronto ahead 2-1 at 18:04, converting a nifty 2-on-1 with Phil Kessel that Miller had no chance on as the Leafs outshot Buffalo 15-7.
Notes: Toronto wore its third sweater for the fourth of eight games this season. ... Toronto entered action leading the NHL in hits (476) and fighting majors (20). ... The Sabres and Leafs will meet once more this season, that being Mar. 21 in Buffalo. ... Rolston has been Rochester's head coach since the 2011-'12 season, having compiled a 63-44-17 record. Prior to that, he spent seven seasons as a head coach with USA Hockey's national program, leading the under-18 squad to three gold medals and a silver in four world championship appearances.