When was the last election that all the toss-up and close Senate races didn't go to the winning party? I see Toomey being like Kay Hagen, someone who is leading or close in the polls until the end but gets pulled under by the wave if Trump collapses.
Maybe 1996? That's the last time I can think of when the tossups split basically evenly.
Also 2002, I think.
Democrats also won LA (indisputably a tossup), NJ (which looked at least strongly R-favored as late in the race as September), AR and IA (maybe not tossup races, but both should've been closer if there was some sort of movement towards the Rs).
2002 is the correct answer, I think.