De Jong himself then went close with a speculative effort from long-range, before Paulo Nagamura grazed the post for Sporting.
It seemed that the away side had stemmed the flow of Kansas chances, but then Roger Espinoza almost scored with a fine shot that had to be tipped away by the goalkeeper.
Portland rarely threatened but almost took the lead on 62 minutes when Fanendo Adi found space in the box and forced the Kansas keeper into a low save.
Kansas squandered more chances late on as Opara sent another header over the bar and Jalil Anibaba nodded narrowly wide from a De Jong corner.
As the game progressed, Kansas became more desperate, but they could not find the breakthrough and had to settle for a draw.