Ignoring the what ifs, I have them losing to at least DRX.
DRX ban Haven (one of the maps Sentinels are willing to play but aren't too good at)
SEN ban Ascent (a map DRX are floating but don't have too many reps on)
DRX pick Abyss (they have arguably the best Abyss in the world right now and SEN has yet to play it)
SEN pick Lotus (a map SEN are really good at but DRX have proven to be just as good as they are... will probably be a close map)
DRX ban Sunset (another one of Sentinels' best maps)
SEN ban Bind (so they can play Icebox)
Icebox decider (another map both teams are good at)
DRX has a slight edge in this veto. DRX should start the series up 1-0 and the other two maps are both 50/50s