Saracens were made to scrap all the way as Mike Rhodes' early try proved enough to see off gritty Glasgow 13-3 at Scotstoun.
The two sides had crossed a combined 57 tries in just six matches apiece in the build-up to their Heineken Champions Cup opener but the expected score-fest failed to materialise.
Instead, the cross-border skirmish proved to be a tense, bad-blooded affair pot-marked by basic errors, inexplicable refereeing calls and numerous feisty head-to-heads.
In the end, Rhodes' first-half touchdown and eight points from the boot of Owen Farrell gave the joint-Gallagher Premiership leaders first blood in Pool 3, leaving Glasgow ahead of what already appears to be a make-or-break trip to Cardiff next Sunday.
Yet it was the Scots who applied the early pressure, winning a scrum penalty on halfway which they kicked to the corner before forcing the visitors into another infringement to earn a kick right in front of the posts.
However, Adam Hastings - son of former Scotland captain Gavin - failed to capitalise as he skewed his kick horribly wide.
If Warriors were in any doubt as to how costly such missed opportunities would be against a side twice crowned kings of Europe in the last three years, Sarries rammed home the point in the 13th minute as they opened the scoring with a move that was fortunate to stand yet no less clinical in its execution.
With two bursts or rapid interchanges, the visitors swept 60 yards up field to within touching distance of the whitewash - although the first should have been halted when Alex Lozowski appeared to be pulled into touch by Ruaridh Jackson.
Allowed to play on by French referee Mathieu Reynal, they worked numbers over to the left, leaving Farrell, Brad Barritt and then Jamie George to feed the ball quickly through the hands to give Rhodes an easy run in.
Farrell added the conversion and then a penalty before Hastings responded by doing what he should have done first time round as he slotted through a kick of his own.
Handling errors halted Warriors' attempts to get on the front foot but their defence looked in good order as they held off the muscle-bound Saracens attack, limiting the Londoners first-half efforts to just another Farrell penalty.
Unfortunately for Dave Rennie's side, the visitors' back-line was just as resolute as they stood firm through four line-out drives in first-half stoppage time. Reynal's stinginess was made clear too, however, as he ignored Glasgow pleas to punish Sarries' breakdown dark arts with a penalty try.
Glasgow spent the opening 15 minutes of the second period scrambling under their own posts.
Their heroic efforts were nearly rewarded as possession was nicked and Hastings booted the ball into the corner, where Rhodes was dragged into touch before he could clear. But no matter how hard Glasgow probed, Saracens refused to crack.
Farrell could have made sure of victory with 13 minutes left but came up short with a 40-metre penalty attempt.
Glasgow continued to fight but Mark McCall's side has a solid chin and they held on to become the first team this season to shut out the Scots.
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