LOS ANGELES (Reuters) - "American Idol" finalist Jessica Sanchez must reach viewers emotionally in order to win the contest this week, while rival Phillip Phillips has a "crazy charisma" that will serve him well in his career, the show's mentor Jimmy Iovine said on Monday.

As "American Idol" approaches its climax on Tuesday, Iovine said he was impressed by both the young singers but gave little away on who he thought would win the 2012 title and a guaranteed recording contract.

Sanchez, a 16 year-old with a big voice but who has been criticized for failing to connect with her lyrics, and Phillips, 21, a singer-songwriter with an indie vibe and sometimes quirky song choices, will sing three numbers each on Tuesday night in a bid for public votes. The winner will be announced on Wednesday.

Iovine told reporters on a conference call that in order to win the contest, Sanchez "has to find that balance between her capabilities and reach inside and have the right song to click the emotion. She has to get people to vote for her who haven't in the past."

If Sanchez wins, she will be youngest "Idol" champion and the Fox TV contest's first female winner since Jordin Sparks in 2007. The home-schooled teen was saved from elimination by the show's judges last month after coming bottom in the public vote.

Record producer Iovine said he was impressed that a singer-songwriter as unusual as Phillips had got to the final, and surprised that he had been overlooked by the music industry before now.

"I think he has crazy charisma and an incredible sound," Iovine said. "He has a certain thing that some of the other (recent 'Idol' winners) didn't have. I don't know how he was missed in the industry because he has such charisma and such a great character."

Regardless of the outcome from Wednesday's finale, Iovine said both singers have promising futures ahead of them.

"(Jessica) is a pro, she is 16 years old.. but when this girl is 18, she is going to do really, really well. She has all the capabilities and all the pieces to just do really great. I get excited when I work with her."

Phillips "has the advantage of being exposed and people hearing him...Now he has to go and make a record that lives up to the popularity and the hype and yet make his first record as an artist, which is not always the easiest thing," Iovine said.