Returning midfielder Paulinho rescued a draw following Shane Long's 12th-minute opener.
"I expected it to be tough. We've seen some top teams come here and struggle this season. They're very capable," said Sherwood.
"But one thing was certain today: if we weren't going to win, we certainly weren't going to lose.
"At the end of the season this could turn out to be a very important point for both sides.
"It was a poor start to the game for us, to concede so early, but I wasn't panicking. There was plenty of time and we grew into it.
"In the latter part of the first half and then the second half we started to dominate, we rolled the ball into (Emmanuel) Adebayor and (Roberto) Soldado in and around the box and looked like we were going to score."