Manchester United have been training with "plenty of intensity" ahead of Wednesday's Champions League quarter-final against Barcelona.
United will be underdogs in the first leg at Old Trafford as they welcome the Lionel Messi-led Blaugrana, who have not lost since January 23.
"As you can imagine, we are preparing for the game with cool heads, but at the same time we are training with plenty of intensity," Mata wrote in his weekly blog.
"We sense what the fans are feeling in the days leading up to the game, and we are sure that the atmosphere at Old Trafford on Wednesday will be incredible.
"We come into this week having lost in the Premier League against Wolves, so it goes without saying that we are aware that if we aren't at our best, fully concentrated and prepared, it will be tough to get a positive result."