The pair previously worked together at Rio Ave and Valencia before the young Scot moved to Newcastle United as Steven McClaren’s assistant and remained in situ when the Englishman was replaced by Rafa Benetiz.
Having started out as a youth coach in Dundee before becoming the head of Dundee United’s youth academy, aged just 22, and then the SFA regional performance school, the only real blight on his career is his term at Tynecastle.
An uncomfortable period for a single-minded young man determined to do things his own way, he eventually reunited with Santo, at Wolves, before following him to north London.
It is a significant move for a man who was often ridiculed during his stint in the Scottish capital and the new job reinforces the belief that while he may not be cut-out for management, he remains a highly-regarded coach.
It is a significant advancement for Cathro, who is still just 34, and justifies his decision to swap his role within the SFA for a place on Santo’s coaching team at Rio Ave, nine years ago.
At that time he had big ambitions but, having quit playing in his early 20s, having never progressed beyond Forfar and Brechin, he felt he would never really be taken seriously in his homeland.
“The only way I would find that sort of employment here is to leave, prove a success and then people here might start to open themselves up to it,” he said. The response to his return, to Gorgie, in late 2016 vindicated his opinion, as pundits lined up to pour scorn on him.
Something wasn’t right, though, and, awkward in the media glare, and criticised for the lack of intensity in his training sessions, and his modern, analytical approach, he returned to a set up that suits him, linking up with his Portuguese pal where he can focus on his strengths.
“In Portugal, the culture and the way the clubs are run from a coaching point of view, the way the technical teams are built, that suits me,” he said when he initially swapped Scotland for his coaching role at Rio Ave. Joining up with Santo, who he had met on an SFA coaching course.
“It’s not like here where it’s the manager and the guy he played with 20 years ago. In Portugal, the idea of a technical team is to get the right people.
“Nuno identified what attributes he has, what was still required and then found the best guy for each of those things.”
It is a recipe for success and has given the Scot access to a top position among the elite, where he is respected rather than ridiculed for what he brings to the table.
But his ambition will not be sated. Arriving at Hearts, he was asked if it was possible to better Celtic and Rangers.
“Let’s not say no to anything,” he responded. “The point is to go in search of where our limit is and not be trapped by anything that’s historical”.
That mournful Hearts spell is in the past and not only is Cathro refusing to be limited by it, he is determined not to be defined by it.