I have watched the race a fair few times, and yes they may have needed to save fuel, but not by much, Hamilton yes as he was constantly harrying the Red Bull's and keeping them honest, while Button was pacing himself like he normally does.
If it was obvious, then Webber after his pitstop repairs would have closed in "at a rate of knots" (another Brundle quote), which he didn't do so.
If it was obvious, then Webber after his pitstop repairs would have closed in "at a rate of knots" (another Brundle quote), which he didn't do so.