Their impressive victory, courtesy of Isidor's winning strike, not only maintained Sunderland's undefeated home record in the Championship but also kept them firmly in fourth place, just two points adrift of a faltering Sheffield United.
Chris Wilder's Sheffield United, winless in three, now trail league leaders Leeds by three points and have fallen behind second-placed Burnley on goal difference. Despite an early penalty miss, they contributed fully to a captivating New Year's Day clash.
Wilder acknowledged the effectiveness of Le Bris's unexpected counter-attacking strategy. "The game was full of pivotal moments," he admitted. "It was a close contest, but credit to Sunderland's manager and players. Their resolute defending frustrated our efforts to find a breakthrough."
The 8pm kick-off on a public holiday, coupled with a public transport shutdown in the north-east, made the 260-mile round trip from Bramall Lane to the Stadium of Light a daunting prospect for fans. Add in the icy conditions, and the 42,276 spectators certainly deserved the thrilling spectacle that unfolded, with numerous dramatic twists compensating for the absence of key players on both sides.
Injuries hampered both teams. Sheffield United were without top scorer Tyrese Campbell, while Sunderland's teenage sensation Chris Rigg was also sidelined.
The tension escalated early on when referee Matt Donohue awarded a penalty after spotting Luke O'Nien's shirt tug on Kieffer Moore. However, Moore's poorly struck spot-kick was saved by Anthony Patterson.
This let-off ignited Sunderland, and they capitalized when Jack Robinson failed to clear Chris Mepham's header, allowing Mayenda to race through and coolly slot the ball past Michael Cooper.
Sheffield United responded through Gus Hamer, whose dangerous cross-shot was deflected into his own net by O'Nien.
While Le Bris is reportedly seeking a new striker, Isidor's continued improvement might make that a less urgent priority. Capitalizing on Sydie Peck's midfield error, the Zenit Saint Petersburg loanee skillfully evaded Anel Ahmedhodzic before firing a low shot past Cooper.
This seventh goal of the season for Isidor gave Wilder much to contemplate. Mayenda and Adil Aouchiche's pace and relentless running exposed vulnerabilities in United's central defense, with Ahmedhodzic and Robinson often left isolated.
Despite seemingly gaining control by switching to a more conventional 4-4-2, Le Bris remained wary of his team's tendency to concede late goals.
This vulnerability had cost Sunderland dearly in recent games, resulting in a draw at Blackburn and a defeat at Stoke. Consequently, despite Isidor's menacing pace and Bellingham's mature midfield display, anxiety lingered at the Stadium of Light as Sunderland withstood a late onslaught from the visitors.
"Our possession game wasn't as dominant as we're used to," Le Bris admitted, "but our counter-attacking speed really troubled them. We're pleased with the outcome today."
