When one thinks of the Sinister Six, Spider-Man comes to mind as most of these Marvel Comics villains have crossed paths with the famous wall-crawler consistently over the years. However, villains don't usually fight just one superhero as other villains have crossed paths, and fists, with other Marvel heroes. In the Ultimate X-Men series, their version of the Sinister Six was powerful enough that it required the entire X-Men team to take them down.
In the Ultimate Marvel universe, this parallel world's version of the Sinister Six consisted of Green Goblin, Electro, Sandman, Doctor Octopus, and Kraven the Hunter who were all incarcerated by S.H.I.E.L.D due to their status as illegal genetic mutations and the crimes their powers allowed them to commit. Introduced as a team in the Ultimate Six (2003) mini-series written by Ultimate Spider-Man writer Brian Michael Bendis and illustrated by DCeased artist Trevor Hairsine, this group of super-villains managed to escape captivity and sought vengeance against their captor Nick Fury. Kidnapping their mutual enemy Peter Parker, they unmasked and humiliated the young hero who had beaten each of them on his own which concluded when they blackmailed him into completing their team by threatening to kill his Aunt May and girlfriend, Mary Jane Watson if he didn't join. They staged an attack on the White House which lead to a conflict with the American super-team know as the Ultimates who were able to defeat the team with Peter's help, turning on Osborn once he was assured of his loved ones' safety. All of the villains were last seen being returned to imprisonment in the prisons below the Triskelion, the Ultimates base of operation.
In Ultimate X-Men Annual #1 (2005) by Brian K. Vaughn, Tom Raney, and others- the Green Goblin is already mid-monologue about his death sentence to their current opponents, the X-Men. This gets a sigh of disbelief from Wolverine as the entire situation is nothing more than a Danger Room simulation, which doesn't mean that the team of teenage (or older) X-Men are in any less danger. Fighting through their opponent's array of abilities, the X-Men talk about their issues with the dialogue and why they're fighting these non-mutant enemies which they are reminded by Jean Grey that they are seen as peacekeepers who must train to fight any kind of threat. Eventually, Iceman suggests they're fighting all these previously Spider-Man foes so Kitty can impress her current boyfriend later which Kitty fires back about Bobby's current obsession with his previous girlfriend Rogue, who recently left the team to be with Remy LeBeau aka Gambit. This back and forth continues for a little bit more as the X-Men balance fighting this unofficial Sinister Six with discussing their everyday life and drama as members of the X-Men with their progress being monitored by their mentor Professor Charles Xavier.
Although it's a short fight it doesn't make it any less entertaining. While the story eventually shifts to the primary tale of Rogue and Gambit's trip to Vegas which gets interrupted by the Juggernaut, this kind of evil team battle is normal for the X-Men and its amusing that Spider-Man is present, even though he is not physically there. It's true that Spider-Man could take each of the "Sinister Six" on individually, he technically wasn't able to do that during their last encounter and required the assistance of the Ultimates to defeat them all.
Whether that makes their version of Peter weaker or stronger than his mainstream counterpart, who has defeated multiple incarnations of the Sinister Six by himself or with a little help, is a question up to interpretation especially since these are Danger Room simulations and not the real villains that the X-Men are fighting. Although that wouldn't be the last time Peter faced this ultimate villain team, one can only imagine his face if Kitty did tell him that her and the X-Men faced the Sinister Six recently in battle. Hopefully, Kitty has enough time to elaborate before Peter puts in a call to Nick Fury to make sure everyone is still safe in their cell.