Forest captain McKenna has been part of a team that has lost only twice at the City Ground this season, while Swansea have won 15 and been beaten just three times on their own patch.
The sides meet at the City Ground in the semi-final first leg on Thursday night, and Mckenna said: "They have quality all over the pitch and have probably played the best football in the Championship this season and we know we are going to be up against it because they have been brilliant at home. That just means that we have to give a good account of ourselves at our place."
He added: "They are going to be two tough games but the first tie will be critical. We need to put ourselves in a position where we are in with a good fighting chance in the second leg because we know they are so strong at home.
"We beat them at our place. We have competed with everyone we have played at home this season."
Swansea gained revenge for their 3-1 defeat at the City Ground in September with victory over Forest in March.
Scott Sinclair's stunning solo goal in that 3-2 win at the Liberty Stadium was recently voted the Welsh club's goal of the season.
Former Chelsea trainee Sinclair made just a handful of Premier League appearances for the London club before getting his first real taste of top-flight football during a season-long loan spell at Wigan immediately prior to his switch to Swansea last summer.
And the 22-year-old forward is eying a return to that level.
"Promotion would mean everything as everyone wants to be playing in the Premier League. It is one of the best leagues in the world," said Sinclair. "It would be a massive thing for the city, the club and the fans if we could do it."Source: PA
Source: PA