NFL coach Eric Mangini was at Mount Smart Stadium on Sunday to watch the Vodafone Warriors' courageous win over St George Illawarra.

In Auckland as owner Eric Watson's special guest, Mangini was at the team's final run on Saturday morning and sat with head coach Andrew McFadden during the game on Sunday.

He was hugely impressed with all he saw and how the Vodafone Warriors coped with a challenging week.

Mangini has an extensive NFL CV, most recently with the San Francisco 49ers where, as defensive coordinator, he was closely involved with rugby league superstar Jarryd Hayne's first season in the code.

He has previously been head coach at the New York Jets and the Cleveland Browns as well as being on the coaching staff at the New England Patriots and the Baltimore Ravens.

McFadden also spoke to Vodafone Warriors TV about Mangini's visit and the prospect of an ongoing association.