Despite going down to a morale-sapping late score against Wales at the weekend - Grewcock insists it's not all doom and gloom for Lancaster's men.
Lancaster's England finish the tournament with a difficult away trip to Paris, before playing Ireland at Twickenham on the final weekend of the Championship - and Grewcock believes there are more positives than negatives from their performances to-date.
"I think England and Stuart Lancaster has done a fantastically good job in the RBS 6 Nations and people shouldn't get caught up on the loss to Wales," said Grewcock.
"I thought the team put in their best performance of the tournament against Wales and it was just unfortunate that the referee didn't see the try in the same way as we did.
"We really saw the boys hitting top form and playing really well together and unfortunately it was against a very good Wales team.
"The final decision right at the end didn't quite go their way but that just shows how close they were to winning that game and going three for three, it was really close.
"So let's not get too disheartened as the team has had a pretty good start and have shown a lot of ability which is important."
Grewcock also hailed the role of skipper Chris Robshaw during this season's RBS 6 Nations/
The Quins flanker, who has only won one cap before the tournament, has not only had to cope with establishing himself in the England side but also with the pressures of captaincy.
"I think Chris has done a fine job as captain and thoroughly deserves the role for the whole RBS 6 Nations," added Grewcock.
"The pressure on his shoulders would have been enormous, not just because he was captain but because he was relatively inexperienced when it came to international rugby.
"But you would never have guessed that he had these things going against him when you look at the start he has made as he has taken to the role with relative ease.
"It is never easy to have all eyes on you but he has fronted up and been counted and won the respect of the squad in the process."
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