He pointed out that the five losses had come against top-level opposition - three to New Zealand and once each to Australia and the Springboks - and that they had been mostly narrow defeats during a period of development.
"This year has been one of transitioning a lot of young players into this England team, which I think have an incredibly exciting future and it's also transitioning the way we're trying to play," Borthwick said at the time having overseen seven defeats in 11 games.
"You can see when the team moves the ball, you see the talent and pace that we have... we just have to make all those moments count and I'm very confident about our trajectory."
Seen through the prism of 2025, it is hard to argue that he did not know exactly what he was talking about as Saturday's superb 33-19 victory over the All Blacks took England's winning streak to 10. They will be aiming to stretch that run to 11 against Argentina next Sunday.
South Africa are now the only leading nation they have yet to beat under Borthwick and though the Springboks seem to be ahead of the rest of the world at the moment, England would certainly not fear them.
Borthwick has been true to his word in moving England on from the kick-based team who came so close to reaching the World Cup final in 2023 to a side that now possesses a real all-court game.
Youthful players such as Tom Roebuck, Immanuel Feyi-Waboso, Ollie Lawrence, Guy Pepper and super-sub Henry Pollock have established themselves as real test performers and Borthwick really has built depth in a number of positions.
Alongside that, some of those he inherited, such as Sam Underhill, Tom Curry, George Ford, Ben Earl and captain Maro Itoje, are operating at "World XV" levels, giving the team a tremendous balance of energy and quality.
"I said that at the time (a year ago) that it's a team that needs experience together and that's exactly what they're doing," Borthwick said after Saturday's match.
"They go away each week and train really hard and are focused on what to improve and that's the kind of thing that's showing on the pitch.
"I think the team has a lot of belief in the preparation, a lot of belief in the way of trying to play, and a lot of belief in the ability that's within the team."
Such belief can only grow after claiming a victory that remains for England a real rarity. They have beaten the All Blacks nine times and drawn twice in 47 matches. The last before Saturday was the fantastic 2019 World Cup semi-final while their last at Twickenham was in 2012.
"Every team has a breakthrough win on their journey, and for Borthwick's England this was it, I think we will look back on it as pivotal," former captain and World Cup winner Lawrence Dallaglio wrote in The Sunday Times.
"They look like a team capable of beating anyone. I think the group have had that belief for a while but now the belief has turned to reality."