Forest travel to take on Blackpool in the first tie on Saturday.
And with Forest unbeaten in their last 20 home games, Blackstock knows any positive result will make the Reds strong favourites to reach Wembley.
"Playing away first is massive. We'll be favourites when we come back here," Blackstock told BBC Radio Nottingham.
"If you get a positive result away from home, coming back to your place it can be massive. It's been somewhat of a fortress at the City Ground."
Forest have won 17 of their last 19 home league games - drawing 1-1 against Bristol City in November and being held to a 0-0 draw by Cardiff in April.
The last goal they conceded at the City Ground was on 6 February in the 2-1 success over Sheffield Wednesday. Since then, the Reds have kept eight consecutive clean sheets.
But before they can seek to make the most of home advantage, Billy Davies's men must confront their own poor away form and overcome a Blackpool side who are unbeaten in eight games at Bloomfield Road.
Forest have not won away from home since January, but Blackstock is not overly concerned by the form of the Seasiders or his side's away-day struggles.
"We need to play our game and do what we've been doing all season," he said. "We need to stay calm and play our football.
"It's a case of everyone keeping their nerve and not getting caught up in the surroundings.
"If we don't perform on the day we will get beaten but if we play to the best of our ability we will win the game - it's fairly simple."
Forest also have plenty of play-off experience to call on.
Davies has previously guided Preston and Derby to the season-ending sprint for the Premier League and is now relishing having done the same with Forest.
"We're looking forward to being there," Davies told BBC East Midlands Today.
"It's a great achievement and what we will do as staff and players is do all we can to put ourselves in to the final and get over the finishing line.
"But irrespective of what happens the fans have to be very proud and, along with everyone else, they should give themselves great credit."
Source: BBC Sport
Source: BBC Sport