Palace were the better team against Tottenham in the opening 45 minutes, but could not take advantage and suffered another heavy home defeat.
Vieira said: “It was a tough night for us. Conceding four goals is difficult to accept, but I do not think that reflects the quality of the game we played.
“We should have scored, especially in the first half. We were not clinical enough and did not take our chances. Hugo Lloris made some good saves and at times we did not make the right decision in the final third.
“We suffered in the first 15 minutes, but then we went toe-to-toe with them, and I have a bad taste, because we did not deserve to lose that game 4-0.”
Butland has six months left on his Palace contract, although the club has the option to extend his deal for a further year.