The promoted Seagulls began the season brightly and topped the Championship table for a number of weeks.
However, they have now not won in six matches, the latest of which was a 1-1 draw with Millwall at the New Den yesterday evening.
"I'm sure there are plenty of positives from tonight's game but we didn't win, and it's been like that for six games now. We need to sort that out," Poyet told the club's official website.
"We are going to win plenty of football matches if we play like we did tonight but we need to improve on a few things, otherwise we will make it difficult for ourselves.
"I feel like we are repeating ourselves but we need to find out why we can't win these football matches when we are so much better than the opposition, like we were tonight."
Poyet's side welcome West Ham United to the Amex Stadium on Monday evening.