Referee Mark Halsey pointed to the spot when Jermain Defoe was tackled by Darren Purse but failed to do so when Robson claimed Erik Edman pulled Rob Earnshaw's shirt in the first half.
Jermain got up and tucked the penalty away himself to level Earnshaw's opener in the 1-1 draw. We did it again in the replay at the Lane on February 12.
Robson said: "I definitely thought that two penalty decisions went against us. Darren Purse said he never touched Defoe and in the first half Earnshaw had his shirt held in the area and that should have been a penalty because it knocked him off balance and was a foul.
"I'm complaining about those decisions going against us but I'm delighted with the overall performance.
"We definitely deserved to win the game and our passing and movement and chances created was as good as at any time since I've been here.
"We managed to maintain the form of the previous few games and the thing is that we have got out of the losing habit.
"Now the boys go into matches looking forward to the challenges ahead because they are not getting beat every week and that breeds confidence."
West Brom boss Bryan Robson insisted a couple of penalty decisions went against his side in Saturday's FA Cup draw.