The Brazilian defender has nothing but praise for the prolific striker and has urged his BVB team-mates to remain focused ahead of Tuesday's return against Real Madrid
The 24-year-old striker, who netted four goals against Madrid on Wednesday, is widely expected to join Bayern Munich either this summer or once his contract expires in 2014, but Santana feels he would be a fine addition for Barca, too.
"Robert doesn't get the same media coverage as Cristiano but he is as good as him. Now he has shown the world his quality and proved he is one of the best strikers in Europe," Santana told AS.
"I think he would fit in well at Barcelona, he has a lot of quality, he is very good with his feet and holds the ball up very well."
The centre-back then went on to discuss Dortmund's chances of making it to the Champions League final at the expense of Real Madrid after their 4-1 first-leg win in the semi-final.
"We are very happy with the win over Madrid. We are just over halfway to making the final. We will do everything again to get to Wembley," he continued.
"But we have to be careful with Madrid, we have to stay concentrated. We are talking about Madrid, a super team, a team that has players like Cristiano Ronaldo, Kaka and Angel Di María, so we'll have to stay concentrated."
The second leg takes place at the Santiago Bernabeu on Tuesday.