Manchester United manager Louis van Gaal says the lack of goals in recent matches is a concern.
The Red Devils scored only one goal in their last four games, Anthony Martial's equaliser away at CSKA Moscow.
And the Dutchman, who was not happy to drop two more points in the table, has urged his players to find the back of the net on Tuesday at home against the Russians.
"Palace showed a lot of aggression," van Gaal told reporters.
"They won every ball in the first quarter of the first half – the second and third ball was always for Crystal Palace, so they built up a lot of pressure on us. But, after 15 minutes, we came into the match and created a few chances.
"In the second half, we could not develop our positional game and could not keep the ball, so we could not create too many chances. Our defensive organisation was good – we didn't give too much away.
"Of course it [the lack of goals] is a concern. I said that after the match against Middlesbrough, when we created a lot of chances.
"You have to finish the chances. In the last minute of the first half, Ander Herrera could have finished it but he didn't. I asked him and he didn't know why, so that is a pity. But I can't complain about the result because I don't think we were the better team today.
"I cannot do anything anymore because we cannot train: we can only recover and recover. We have to score in the next match and then everybody will be happy again, and especially against CSKA Moscow it is very important to score.
"I am not happy [overall] because if you want to be the champions, you have to win these kinds of matches. Arsenal beat Swansea, for example. We lost against Swansea, even though we were the better team, but they have beaten them 3-0."
