Leinster went through the Pool stages as the only unbeaten side in the competition, rattling in 33 tries in their six games, but have to tackle Leicester Tigers before they can ever consider playing Toulouse.
"We could have one of the most exciting and high-scoring games of all time if we get a Leinster-Toulouse semi-final," Ntamack said. "Leinster's backs are very similar to Toulouse and they always look to run the ball.
"Just imagine what the scoreboard could look like if these two teams clash. But before that we have to play against Northampton, which we know isn't going to be easy.
"They beat us in the Pool stages this season and we met them in Toulouse in the quarter-finals in 2003. That was in front of 37,000 people at our Stadium, so we will know what sort of occasion and game to expect."