The Baggies have given themselves a great chance, as they are in second place with one game remaining.
But they have slipped up in recent rounds and could miss out if they fail to beat QPR on Wednesday night.
Bilic knows it is a must win game, and they have not won in their previous three matches.
"That's where we belong [in the top two]," said Bilic to reporters ahead of the QPR game.
"Now one game before the end of the season, we are in a position to cross the line.
"We are confident, we are optimistic, I'm extremely positive that we are going to do it. We are ready for the game on Wednesday."