The striker made the observations after scoring a late equaliser in the 2-2 draw against West Ham United which saw Sunderland slip ever closer to relegation from the Premier League.
The Black Cats are no strangers to wriggling clear of the drop in recent years but they now look doomed as they sit nine points adrift of 18th placed Hull City with six games left, having been rooted to the bottom of the table since mid-January.
"It's harder than previous times I think," Borini, who scored a late equaliser against West Ham, told the BBC.
"We have not been at our level and we have not been a united group as previous seasons. That's what has been the problem.
"(Our struggles are) a little bit because of problems within the dressing room but that's for us to deal with it. Even the results, the injuries, that's all part of being united and keeping believing."
Last season, Sam Allardyce helped Sunderland finish two points and one place above the drop zone while only three points and two places saved them the previous year.
They survived in those campaigns thanks to a stunning late run of form but they have won just five times all season under David Moyes and, crucially, just once in their last 10 to stop them building the sort of momentum which saved them before.
"Positive results like today, and performances, can bring that strength to the group and get everyone together because in our situation we can only get out together, not individually," the Italian added.
"We've been missing loads of players. The list is massive and that has been the problem.
"We all know we are Premier League players, we've been playing in the Premier League a long time and surely I don't want to get relegated."
"We'll keep believing while we're in with a chance, and somewhere along the line hope the football gods will shine on us," Moyes said. (Reporting By Tom Hayward; Editing by Ian Chadband)