"In a season with radical changes, we based our investment strategy on a three-year plan but after reaching the halfway point of this season, we have so far fallen short of the objectives," Godinho Lopes wrote in the club's newsletter.
The 2-1 loss at Braga left Sporting trailing leaders Benfica by 11 points, Porto by nine and they are three behind last year's Europa League runners-up Braga.
"We are aware of the points difference... it is out there for everyone to see. Sporting have to do more and to do it better to win," Sporting coach Domingos Paciencia told reporters.
In a twist of fate, it was unfancied Braga, Paciencia's previous club where he enjoyed so much success, who dealt the latest blow to Sporting's title aspirations.
"No-one can be happy, and the players even less. This was not the game we wanted," Paciencia said.
"I am confident that, match after match, we will arrive to the level we aimed for and place Sporting where it deserves," Lopes said.
