The men in red and black stripes have not won in six games in all competitions and have slumped to 10th in Italy's top flight, 15 points adrift of the UEFA Champions League qualification spots.
Milan had 68 per cent possession in their 0-0 draw away to Chievo last week and they took 23 shots to the home side's five, while in their previous four matches, Massimiliano Allegri's side conceded in the final 20 minutes.
Matri said he believes his team's inability to take their chances and their tendency to concede late goals comes down to Milan's focus.
"There's a lot of desire to get back," Matri told Milan's official television channel on Thursday.
"We know we're not doing as well as we can and that's why there's this desire to get back on our part. We always train well but obviously that's not enough.
"We have to push ourselves and look after the details. Concentration is a key factor at the moment."
After this weekend's international break, Milan will resume in Serie A with a game against Genoa, who sit three spots above Allegri's team and have won three straight matches.
