I hate to judge players soley on their mistakes, but with central backs, that is often all we are left with.
On the first goal, Whitbread left Bale to help 2 other players cover Adabayor, that was a decision he got wrong and Bale had an easy goal when Adabayor slipped him the ball.
On the second goal, he started late, that gave Bale a clear route and he took it. Some defenders catch attackers, who must both control the ball and run while the defender must simply sprint. The second goal was another poor (or maybe just too slow decision) and then not enough pure speed to recover from the error.
On the bright side, Whitbread made several aerial clearances and did well in general in covering the central route to goal.

I wouldn’t judge Whitbread on this one game.

Bale has made a lot of players, not just center backs, look slow and foolish.

Whitbread isn’t the first and won’t be the last.

Bale torched Maicon repeatedly in the CL. No need to focus on how slow the defender is (especially a center half like Whitbread). Bale is ridiculously fast.

Do we want to focus on Bale being super fast or Whitbread being slow?

It may be nice to have a potential USMNT CB starting in the EPL but if you lined up the 40 starting CB’s (2 for each team) in the EPL best to worst, he’d be very near the end of that line.