England defence coach Felix Jones has enjoyed remarkable success in his short coaching career, but has yet to beat his home country Ireland.

As a player, perhaps his greatest moment was helping Ireland win the 2015 Six Nations, earning his penultimate cap in a crucial 19-9 victory over title rivals England.

Now Jones is focused on beating a relentless, confident and expertly-coached Ireland side chasing historic back-to-back Grand Slams.

Robbie Henshaw, Peter O'Mahony, Cian Healy, Conor Murray and Iain Henderson all played with the England defence coach that day and will look to challenge Jones' new system on Saturday.

"As soon as you become a coach you become aware it is a professional game and you are going to be moving from a club or international team to another one," Jones told the BBC's Rugby Union Daily podcast.

"It is like it is normal work and you treat it like a professional game.

"It doesn't pull on the heart strings now."

After a serious neck injury forced him to retire at his peak in 2015, the full-back became part of Rassie Erasmus' coaching team at Munster.

A few years later he followed Erasmus to join South Africa's coaching staff and helped the Springboks claim World Cups in 2019 and 2023.

"It wasn't a career path that I had in mind," added Jones. "It was more just an opportunity and a couple of things fell into place.

"I got quite lucky with a couple of mentors that guided me along the way."

'He always went above and beyond'

The former Ireland and Munster full-back's qualities stood out from the start of his professional career.

"He was always an avid student of the game, his knowledge and work ethic are second to none," former Munster team-mate Johne Murphy told BBC Sport.

"He always went above and beyond, talking to players and getting different people's opinions. Just sparking conversations around what we could have done there or done differently.

"As such a standard bearer it was a very easy transition into coaching as people always listened to him and his opinion carried a lot of weight."

As a player, Jones played 13 times for his country, missing out on the 2011 World Cup because of injury.

"Through injury you didn't get to see the best of him in an Ireland shirt, but he was a top, top-class player," the former Munster wing added.

"His GPS data sums him up. No-one would have been within a 1,000 metres of him in terms of distance covered in a game. They were off the charts.

"That shows his work ethic and wanting to go further than anyone else."

England have conceded eight tries in their opening three Six Nations games, with errors in their system being exploited in every game.

It is hard to learn a new system in a short tournament window, but Jones' "depth and intensity" is helping England accelerate their development.

"His laptop is a joke," number eight Ben Earl told Rugby Union Daily. "The amount of files he has open, games he has watched and clips he shows us."

The challenge on Saturday, however, is keeping out an Ireland side who have scored 15 tries in three emphatic wins.

What can England learn from New Zealand?

Ireland's narrow quarter-final defeat by New Zealand at the World Cup was their last loss. The All Blacks scored two tries through moments of individual brilliance in "unstructured rugby", which Jones wants England to learn from.

"Pressuring their time and space becomes a big deal with their levels of skills," added Jones. "Every single player in their team has the ability to play passes.

"What New Zealand did do well is when they were presented with an opportunity - on their own set-piece or turnovers they created - they were able to exploit that.

"If we can force turnovers, as we have done over the last three games, then hopefully we can capitalise."

His last meeting with his former team during the pool stage of the World Cup ended in a rare Springboks defeat, but that will have given him even more files to review and more stats to crunch.

England will need every advantage they can get on Saturday.