Former All Black captain and current expert analyst Sean Fitzpatrick forgot he was on-air when he ripped into celebration moments after Richie Mo'unga kicked the All Blacks to victory in the final seconds against South Africa.

Commentating for Sky Sports UK, Fitzpatrick hilariously switched from professional mode to All Black fan in the blink of an eye when he was caught on camera fist pumping New Zealand's come-from-behind win.

Former South African great and co-commentator Bobby Skinstad's face dropped in despair, a painful contrast to Fitzpatrick's fists proudly raised in celebration in the background.

The moment was caught by Sky Sports cameras much to the delight of Kiwis around the world.

"Fitzy's celebration shows no matter whether you're working or what you're doing, being an All Black fan comes first ahead of anything," one person said.

Another wrote: "Crack up! Fitzy is how EVERY New Zealander feels around the world right now.

"Seeing the All Blacks win means everything."

Debate is raging whether the All Blacks' 32-30 comeback win over South Africa this morning is one of the greatest comebacks in history, with some comparing it to the All Blacks' victory after fulltime over Ireland in Dublin in 2013.

The All Blacks, very ordinary for large periods, looked dead. Down 30-13 in the final quarter, the inspired Springboks were in total control.

The All Blacks had no right to win. But with one of the best responses you will see they somehow rallied to stun the locals.

Three second-half tries to Aaron Smith, Rieko Ioane and Scott Barrett got them within touching distance of the seemingly unthinkable.

Just when it seemed the Boks would back up efforts in handing the All Blacks their first home defeat since 2009, victory was stolen from them - a sign the All Blacks number 1 rating is far from being challenged.