Methinks Lewis knew well enough that he had the measure of Nico. Would he have moved over had Nico got close enough? Hmm, I suspect not. In fact his positioning of his car and little jink when Nico made his last gasp attack showed that he knew exactly where Nico was and what he would try to do. That was a supremely artful defense.
Unfortunately, one drawback for the team in those final laps was that Lewis had to split his attention between attacking Fernando and defending against Nico. Any experienced racer will tell you that squabbling over a place will slow all those involved in it. The best tactic for the team would have been to ensure that Nico was not a threat to Lewis whilst he was in with a chance of getting into DRS range of Alonso. It was noticeable that Alonso managed to grab back a few tenths here and there as Lewis had to position his car defensively.
Further, there was a brief spell in the commentary when Brundle grumbled about Hamilton losing some time. A minute or so prior to that a brief moment was caught on camera of the group catching some back-markers. Martin and Crofty failed to notice that Alonso was just clearing them cleanly at the end of the straight but Lewis and Nico were probably compromised as they caught the traffic in the corners. It may be, that while fending off Rosberg, had Lewis not lost a couple of crucial tenths on Alonso he might have been able to close in, follow him more cleanly through the back markers and to continue to press. Without a report from someone track side, though, I admit I'm speculating somewhat. Nevertheless, putting Hamilton on the slower tyre and then compromising his attack on Alonso was not the smartest move on Mercedes part. I suspect, or at least hope, that they will not make that mistake again.
One very good thing (apart from a great race, that is) that has come out of this, is that Hamilton is showing that he is at last sticking up for his own interests on track. that was something that he seemed not to do at MacLaren. All too often his strategies and direction were dictated by MacLaren's mission control. If Mercedes can get the balance right, and stop this contra-strategy bollocks, then we should see a fairer fight between their drivers for the title and the cream should rise to the top. If Merc' don't achieve that the cream at the top may actually turn out to be a tad sour.