Scala - increasing prefix of a sequence

Question

I was wondering what is the most elegant way of getting the increasing prefix of a given sequence. My idea is as follows, but it is not purely functional or any elegant:

Answer 1

And, another way to skin the cat:

 val sequence = Seq(1,2,3,1,2,3,4,5,6)
 sequence.head :: sequence
                  .sliding(2)
                  .takeWhile{case List(a,b) => a <= b}
                  .map(_(1)).toList
// List[Int] = List(1, 2, 3)