Windies skipper Chris Gayle felt his side let England off the hook after looking set for long periods to complete a Twenty20 double.
He said: "With something like 40 runs to get from the final four overs I thought we were in control. But I thought they batted well and capitalised on the mistakes we made in the field so you have to give credit to them.
"You have to give credit to Shah. I thought he really showed a lot of composure, taking the game home for England. He's not really a big-hitter of the ball but he rotated the strike which is very important and picked up runs here and there.
"But overall it has helped us a lot playing these two Twenty20 games and they will make a big difference going into the first one-day game on Sunday.
"I thought the guys' preparation was really good leading into these games and hopefully the guys can make the most out of this opportunity and we're now looking forward to Lord's."