"Nelson was on a different strategy, carrying 30 litres more fuel (thats another fifteen laps)."
After the running on Friday Renault have an idea where their drivers are regarding pace. Obviously Alonso had a lot more pace and could go for the aggressive strategy where as Nelson was struggling and had to go heavy and hope for a pace car incident. Nelson has struggled a lot with bad practice pace so he had to go, look at Felipe Massa he was in the same situation a few years ago when he was only the Ferrari test driver for a year and made a better come back a year later. Just because his dad was great it puts a bit more pressure on.