There's no ambiguity. The Quar'an states that Jesus was born of a virgin and as such, he's a prophet/messenger of God.
There's an entire section of the Qur'an dedicated to Mary (Surat Maryam). If you visit a shrine to Mary, you're likely to find as many Shiite pilgrims as you do Christian pilgrims.
Muslims also believe that on judgment day, Mohammad will join Jesus and some other prophets as God sits in judgment over people.
While the Qur'an believes both the old and new testaments, it also introduces some additional language to formalize "recruiting" into God's world as well as "family planning"."
Kind of like the Book of Mormon, which was found by a lizard or something in some field in New York, and was God's latest and greatest word.
If you have any questions on the latter, I'm sure the Mormon Church will be tickled pink you're interested.