And Gloucester head coach Bryan Redpath spoke in similarly glowing terms of Freddie Burns after a match in which all the points came from penalties.
The fly-half pair ensured the tussle finished 15-15, with the spectacle far better than the wet conditions at Vicarage Road should have allowed.
Saracens were two minutes from victory when referee Sean Davey penalised them for collapsing a driving maul, and Burns delivered a draw-earning kick in the downpour.
Farrell, 20, and Burns, 21, gave mature performances, both scoring five penalties.
McCall said of Farrell: "The remarkable thing is that Owen rarely misses two kicks at goal in a row. When he misses, the next attempt usually goes over which is the sign of a top-class kicker.
"He did a very good job in very difficult conditions, and while we were always on top, we were unable to pull away from them."
McCall was also delighted with full-back Alex Goode, one of a number of young England-qualified talents being watched from the soaking sidelines by England's interim head coach Stuart Lancaster.
"Alex was tremendous, in my opinion back to his best and posed a definite threat with his strong carrying and running," McCall said.
"There were always going to be errors in such difficult conditions and both side made them.
"Burns also kicked very well, but when you add up those errors they tend to prevent you building momentum."
McCall was willing to discuss rumours that Northampton and England wing Chris Ashton has been linked with the club - but not beyond acknowledging the player's attributes.
McCall said: "Ashton is an outstanding player who will clearly get better and better the more he plays.
"But we are linked to a number of players on a regular basis, so if and when we have news of something we will let it be known."
Saracens lost Schalk Brits shortly after the former Springbok hooker had come on for Jamie George.
McCall said: "He took a bang on the shoulder he hurt at Twickenham, right on the same spot. We'll know more later in the week."
Redpath is convinced Burns will soon be the finished article in fly-half terms.
"Freddie is maturing in terms of steering the team and running a game," Redpath said.
"I am delighted with the way he coped with the conditions and kicked his goals.
"He is learning that the team's performance is more important than his own. He sometimes tries to do things on his own but he is learning with every game.
"I'll take the points because we were never ahead in the game and it's a good away result."
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