Moussa Sissoko is at a loss to explain Tottenham's lacklustre Premier League form after Mauricio Pochettino's men laboured to a 1-1 draw at home to Sheffield United.
Son Heung-min's 58th-minute opener looked to have been swiftly cancelled out after David McGoldrick netted for the Blades but a marginal VAR call went against John Lundstrum earlier in the move.
Spurs could not make the most of that reprieve as George Baldock netted a deserved 78th-minute leveller, extending the north London club's winless run in the Premier League to five matches.
"In the league we are struggling since the beginning of the season. Why? I don't know because we are trying our best but it is not working," France midfielder Sissoko said.
"We see today it was a difficult game against a good team. We were winning 1-0 but didn't keep the score. We have a lot of frustration but need to keep going.
"We have to stick together, like we said every time, and try to work hard."
It will be almost two months since their previous Premier League victory when Tottenham return from an international break Sissoko hopes will serve as an opportunity to reset.
"Every team can have some difficult moments," he added. "We are struggling in the league and that's football.
"We must keep working, give our best every day until everything turns around
"We will fight until the end. We know we can do better
"Now we are going away with the international teams and we have to come back stronger."