Torrance, the 82-year-old father of Ryder Cup great Sam, moulded Harrington into a three-time major champion during an all-conquering alliance that brought two Open Championship crowns and a US PGA title between 2007 and 2008.
As Rory McIlroy moved into a four-shot lead at the halfway stage of the 143rd Open Championship at Hoylake yesterday, many were left reflecting on the passing of one of the game's most dedicated and knowledgeable coaches as the sombre news filtered through.
Harrington, the 42-year-old Dubliner who worked with Torrance from 1998 through to 2011, said: "I loved him. He was a father figure to me. And still was, even though we stopped working together.
"I was there a few weeks ago and it was very difficult to see him in that situation. Knowing Bob's pride, which he sure had, it was probably better for him not to go on too long.
"But this is a day to remember the great things that Bob did. It's kind of appropriate that he died during the Open Championship. He's getting back into golf again. He probably watched the Open all the way to the very end."
Harrington, one of the game's hardest workers, found a kindred spirit and their work ethic would reap a handsome reward as the Irishman finally elevated himself into the rarefied air of a major champion. It was the perfect match.
He added: "My majors would never have happened without Bob. Not a chance. He was absolutely a critical part of me winning major tournaments. You know, you want to see the kind of ball striker I was before I started working with him. He did a phenomenal job. I completely rebuilt my swing under Bob and it was always a joy to do it. He was a great person to be around.
"We were a perfect match. Because all Bob wanted was somebody to stand on the range with him. Somebody who would spend as much time out there as him. I brought a short game and mental game, putting and all that, so we spent all day on the long game.
"Bob believed the only time you had to chip was chipping back to par fours. We would start at nine in the morning, come down for lunch, practice until six o'clock and then be at it another two or three hours after dinner.
"The energy of the man was phenomenal. Nobody could put more effort into the game than Bob Torrance."