Ireland wing Mack Hansen described Saturday's 13-8 win over reigning World Cup champions South Africa as a "Grand Slam on steroids".

The win underlined Ireland's status as the world's number one team after their Grand Slam in this year's Six Nations.

"They are so big and physical and they showed up tonight. The fans got us over the line there," Hansen told ITV Sport.

"It was like a Grand Slam on steroids out there. It was crazy."

"It seemed like there was 800,000 [fans at the Stade de France]. It was incredible out there and we needed every single one of them to get a job done against a really good South African side."

The victory leaves coach Andy Farrell's side clear at the top of Pool B and with one foot in the quarter-finals, where hosts France or more likely New Zealand would await.

Ireland have never got past the last eight of a World Cup and Hansen says his side will switch their focus to Scotland on 7 October to ensure their place in the knockout stages is secure, rather than looking ahead to any potential quarter-final.

"They are the defending champions and they know exactly what it takes to win this World Cup," Hansen added about South Africa's challenge.

"To get a win over them is as good as it can get really. It gives us a lot of strength and a lot of belief.

"We have a tough week against a really good Scotland side and if we get the win there, and everything goes well, it's either France or New Zealand [in the quarter-finals].

"It doesn't get any easier at all. We'll take this win and enjoy it for now, then it is straight on to the next."

I've never witnessed anything like it - Aki

After scoring four tries in Ireland's opening two matches, Bundee Aki produced another player of the match performance as the men in green made it three wins from three in Pool B.

After the match, the song Zombie was sung by the Irish support and drowned out the public address system that was playing the Cranberries classic at the Stade de France.

"I'm lost for words. These Irish fans are incredible," said Aki.

"Honestly, I've never, ever witnessed anything like it, the travelling crowd.

"It's a joke, completely a joke and it's only going to get bigger and crazier from here on in.

"Fair play to the boys for playing that well today. South Africa are an outstanding team. They are world champions for a reason."

Aki said he knew the Springboks' challenge would be strong and said that the Irish mentality was key in getting a result against the reigning champions.

"As a group and as a team we knew coming into this game, we knew we had to be a lot better than the previous games, in all areas of our game," the centre added.

"We knew South Africa were going to bring it to us and look, they did. They put us under an immense amount of pressure but we trusted each other and the belief we have in this group is outstanding."