The Giants D got a safety on the second drive of the game. The Giants O drove 79 yards to make it a 9-0 game in the second quarter. The D gave up 10 points on 3 NE drives in the second quarter and another 7 points at the start of the 3rd quarter to make it 17-9. Why does it matter when they blew the lead? They blew the lead but held NE to only 17 points. That is what really matters. How many points you give up and how many opportunities you give to the O to take the lead. NE's O was given plenty of opportunities to increase the lead which they never did. The NE D never allowed the Rams to take the lead. The Giants D did. The NE D gave up 17 while scoring 7 and putting the O on the 33 and 40 yardline. All the NE O needed was 2 scores to win the game and they were put in outstanding FP 2 times.
The Giants D gave up 17 points while scoring a safety and the best FP they had was at the NE 48. The O needed to score 3 times and were only in good FP once.
Both played great, but overall the NE D played better. Ask any coach in the NFL which defensive game he would take. A D that hold the opponent to 17 points while scoring a TD and putting the O on the opponents 33 and 40, or a D that holds the opponent to 17 points while scoring a safety and puts the O on the opponents 48. They won't care if the points given up are spread out equally through 4 quarters or if they all came in 1 quarter. All they care about is the total amount and if the O had opportunists to win it. All they would care about is the fact that they only need 2 scores to win and would have the ball on the opponents 33 and 40 yardline. That is a much better situation than needing 3 scores and the best FP being the 48.
Holding a great offense under 20 pts doesn't mean much when you are losing in the last couple minutes of the game. If Brady rescued the NE D when the game was tied, then Eli did more for the Giants D when they were losing.