If Stevie makes that grab--again, I don't mean to harp here, but let's be serious--then it's first and ten at the New England 45ish, with about 8 and a half minutes to go and the clock running. One more first down, and they're in field goal range, probably 6 minutes to go. Even if the drive stalls then, they get a decent look at a field goal with about 4 minutes to go. They make that, and New England HAS to score a touch down, something they only did when turnovers put them in the red zone (or damn close.
So, even though Spiller's execution on the first down run, and the bad pass on second were poor examples of "execution," under much easier circumstances, simple execution would have made a win much more probable.