The Red Devils have endured struggles at both defending and attacking from set pieces.
But they held firm at the back and scored from a corner to defeat Chelsea 2-0 at Stamford Bridge in the Premier League on Monday night.
And Matic admitted they worked hard on corners and other set pieces during their winter break.
"Yeah, I think this is the first or second goal we've scored in the league from a corner, so I'm happy," the Serbian told MUTV after the match.
"I'm happy because we worked a lot on that in the last few days. It's a strength for the future, now that we can count on goals from headers.
"I'm happy with the team performance and we have to continue like this."