Suggested by Sonic Bayonetta is incredibly fast and also has some solid regenerative abiliites. This will keep her in the mix against Saber for a longer period than she could otherwise, but Saber still has the absolute edge here. Her Excalibur attack would destroy Bayonetta without a trace. Her speed is also crazy enough where Bayonetta would not be able to regenerate quickly enough to match all of the blows. Ultimately that will end up with her defeat as a result. Saber wins.