After they clinched the Premier League title last weekend, a victory at Wembley would give Chelsea the first Double in club history.
Pompey was able to shock Spurs in the semi-finals with a 2-0 extra-time to earn a chance to win their second FA Cup title in three seasons.
Ancelotti has given credit to Pompey manager Avram Grant for the job that he has done with under extraordinary circumstances and believes that Chelsea must respect the Championship-bound club.
“I learnt from the semi-final between Spurs and Portsmouth that if you don’t prepare well, you can have difficulty playing against them,” Ancelotti told the Daily Star.
“Also, we have a lot of respect for the opposing team, who did a fantastic job to get to the final.
“Avram Grant is a very good coach. He was at Chelsea for one year, played the League Cup and Champions League final and did a very good job.
“Portsmouth have had a difficult year, but he did well to take them to the final of the FA Cup.
“We have to play against players with strong, strong motivation.”
The Italian admitted that he did not understand how special the FA Cup was until experiencing it for himself.
“I didn’t know before this season how special the FA Cup was and how important it is for every club.
“It’s the oldest competition in this country. I know now there was a lot of surprises, a lot of little teams played important games; Leeds beat Manchester United, Liverpool lost to Reading.
“For us, it’s a great opportunity to win the Double for the first time for this club and we can do this.”
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