United could certainly have done with Mata, who has scored 10 goals in all competitions this season, and banned striker Zlatan Ibrahimovic at Old Trafford.
The draw left United fifth in the Premier League and five points off the final Champions League place open to English clubs, with local rivals Manchester City occupying the coveted fourth place in the table as the season heads towards its conclusion.
"It was a shame that we weren't able to get the three points because now we would be in a better position, but we have to keep going," said Mata in comments published Monday on his website, juanmata8.com.
"We had some chances to score that goal that sometimes is so difficult to get, but we couldn't make them.
"Now we have to focus on the next game against Everton at home this Tuesday, and try to win this one.
"At this moment we're being unlucky in terms of players injured or suspended. I hope the situation gets better from now until the end of the season."
Mata, who underwent surgery on Friday, admitted he had found being reduced to the role of a spectator difficult.
"Watching a game of your team on TV is not the best possible experience, but I had to do it on Saturday," he said.
"As you can imagine, I'm writing this post in not the best possible situation, but first of all I'd like to thank you for all your messages of encouragement during the last few days.
"This situation is new for me, after having surgery, but I feel positive and I'm looking forward to getting well and trying to help the team. Besides, right now your messages of support are like an extra power for me."
United will have both Ibrahimovic and Mata's compatriot Ander Herrera available to face Everton after they each completed bans.
Ibrahimovic missed three matches due to his elbow on Tyrone Mings and midfielder Herrera two games following his red card during the FA Cup loss at Chelsea.