Norwich City manager Alex Neil questioned whether Sunderland's first two goals should have stood after seeing his side lose 3-0 at Carrow Road.
Sunderland opened the scoring in Saturday's basement battle when Andre Wisdom chopped down Fabio Borini in the area four minutes before half-time with the striker getting up to tuck away the penalty.
Jermain Defoe added a second in the 53rd minute, but Neil felt Sebastien Bassong had been fouled in the build-up and also had doubts about the penalty.
"I think you could argue the big decisions didn't go in our favour," he said.
"I've said to the players if we are going to do it, then we are going to have to do it the hard way."
Duncan Watmore completed the scoring for Sunderland in injury-time as Norwich missed out on the chance to move seven points clear of their rivals and are now just one point ahead in the battle to beat the drop, having played one game more.
And Neil believes his side must now win at least two of their remaining fixtures against Arsenal, Manchester United, Watford and Everton.
"We've got four games remaining and we need to win at least two," he added.
"But you have to bear in mind the other teams are still chasing us. Sunderland have got to win that game in hand to make it count.
"However, if we don't win games between now and the end of the season then it won't be enough."