Saracens raced clear in the second half through Maro Itoje, Nick Tompkins and Jamie George tries.

A Duncan Taylor intercept capped Sarries' dominance, before Louis Rees-Zammit scored a late consolation.

Gloucester came into the match having won four of their past five home knockout fixtures in this tournament and Wales wing Rees-Zammit came within inches of a perfect start, almost dotting down his own kick.

Much to the dismay of the Kingsholm crowd it was as close as the Cherry and Whites would get to the Saracens try-line for the majority of the half.

Farrell kicked a penalty, his first of a 100% record in front of the posts, on a night when he scored 19 points. Prop Vincent Koch then punched a hole in the Gloucester line, running into acres of space and passing to Davies to cross under the posts.

Saracens' ruthlessness shone through as they dominated the breakdown and halted Gloucester's usually effective driving maul. The hosts' penalty count racked up and things became worse when Ollie Thorley - making his 100th appearance - was sent to the sin-bin for a high tackle.

As Thorley returned, Saracens saw England prop George given a yellow card for his own high tackle and Gloucester used the advantage to get their first points on the board, finally driving over at their fourth attempt from a line-out for Singleton to score.

There was a flicker of a comeback after the break as Hastings' penalty brought Gloucester to within eight points. Yet it was extinguished immediately when Itoje scored from close range, as Saracens made almost every visit to the Gloucester 22 count.

With prop Val Rapava-Ruskin next in the bin, Tompkins scored Sarries' third try and George followed, as Saracens played Gloucester at their own game and launched powerful driving mauls.

Taylor put the icing on the cake, snatching a loose pass, and while Rees-Zammit's late try was stylish as he chased and regathered his own kick from his own half, Gloucester were bettered in every area across the pitch.

Three-time Champions Cup winners Saracens progress to another European final four, albeit this time in the second-tier Challenge Cup, and face the winner of Sunday's match between Toulon and London Irish.

Gloucester, meanwhile, will turn all their attention to the Premiership knowing they face Saracens again on the last day of the season.

Gloucester head coach George Skivington told BBC Radio Gloucestershire:

"Obviously the scoreline is not very flattering, but it gives us a good check point to see where we are at with a few areas.

"I thought we made it easy for them the second half, if I'm honest, with the amount of penalties we gave away. I think they came from a good place, I think the boys were trying to get us on the right foot but we gave them off the kick-off three penalties straight away.

"Lots to learn, we step away from it, I thought they were very, very good, they are very good. And we'll definitely learn some good lessons tonight."

Saracens director of rugby Mark McCall:

"This was a big step forward from where we have been. The atmosphere was terrific and vastly different from the game at Worcester last week.

"Most of the areas of our game were really strong and we generally capitalised when we set up opportunities.

"Inevitably good players relish big knockout games. Billy Vunipola had an incredible first 15-20 minutes as his ball-carrying was a different level.

"Big Maro (Itoje) was back to near his best and Owen Farrell led the team magnificently.

"The next two weeks are a crucial part of a season. We have a tough semi-final in Europe followed by a home game with Northampton, which we need to win to ensure a home semi-final in the play-offs."

Gloucester: Carreras; Rees-Zammit, Harris, Atkinson, Thorley; Hastings, Chapman; Rapava-Ruskin, Singleton, Balmain; Clarke, Alemanno, Reid, Ludlow (capt); Morgan

Replacements: Socino, Elrington, Ford-Robinson, Davidson, Clement, Meehan, Twelvetrees, Seabrook

Sin bin: Thorley (16), Rapava-Ruskin (49)

Saracens: Goode; Segun, Daly, Tompkins, Maitland; Farrell (capt), Davies; Mawi, George, Koch; Itoje, Swinson, McFarland, Earl; B Vunipola

Replacements: Pifeleti, Barrington, Clarey, Isiekwe, Christie, Van Zyl, Taylor, Lozowski

Sin bin: Jamie George (25)

Referee: Frank Murphy (Ireland)