Bath were exceptional in the early stages of this fascinating Premiership derby; indeed, they were almost as exceptional as they will have to be in San Sebastian in six days' time. Everything connected, to the extent that the stand-out player on the field, the Samoan No 8 Isaac Fea'unati, claimed the outstanding try of the game - perhaps the finest try of the season, despite Bristol having two forwards in the sin-bin when he scored it.
After 49 minutes of the 40-minute session (another little teaser for the physicists), Joe Maddock stripped the ball off David Lemi and launched a move from his own line that beggared the belief of Bath aficionados still struggling to come to terms with the fact that, with Ashton in charge, such things are possible. The ball went left towards Andy Beattie, who raised a gallop down the touchline; the ball went right, at which point Olly Barkley contributed the most delicate of defence-befuddling kicks. Once Maddock had gathered at pace to free Salesi Finau, the spherical centre fed his fellow South Sea islander for a glorious completion.
"That is precisely how I want us to play," said Ashton, happy in the knowledge that every other coach on God's earth would want his team to do likewise. "It's about the recognition of opportunity, as much as anything. If a chance arises, it doesn't matter where on the field you might be. Don't take the soft way out and kick the ball away; attack the opposition instead. We looked as though we'd taken a wrong option early in the move, but we backed ourselves to play ourselves through the problem. There were a lot of good things in that try: running, kicking, offloading, all performed to a high standard. It was a satisfying moment."
Yet satisfaction and clarification are two different things. Ashton is wrestling with back-row issues of the most complex variety: the perming of the best three from four extremely accomplished players - Fea'unati and Beattie, Michael Lipman and Gareth Delve. On the face of it, the 32-year-old Fea'unati began this game as most vulnerable, under pressure from Delve, a decade his junior. Yet the Samoan was so direct and powerful during his 53 minutes on the field, no fair-minded selector could seriously consider demoting him for the club's biggest game in more than eight years.
So if not Fea'unati, who? In the quarter-final against Leicester on April Fool's Day - an appropriate piece of fixture scheduling, given the nature of the Midlanders' performance at the Walkers Stadium - it was Lipman, the least physically imposing, who sat on the bench. Yet the Australian-born flanker muddied those waters on Saturday by claiming a stream of turnovers as Bristol muscled their way back into contention after the interval. "It will," conceded Ashton, "be a desperately difficult decision."
This was some effort by Lipman, for his opponents - Matt Salter, the tough-as-old-boots Bristol captain, and Joe El Abd, who absorbs punishment as a kitchen towel absorbs spilled coffee - were in full warpaint. Andy Robinson, the England coach, may even be tempted to give him a trip back home when the world champions play their summer Tests in Sydney and Melbourne. His performance was not wildly dissimilar to those that defined Robinson's own career at the Recreation Ground.
Come the evening kick-off, the Bristol players had heard the result of the London Irish-Leeds game and knew they were safe from relegation. Bath were equally blessed by events at the Madejski Stadium, but Ashton declined to inform his charges. It explained, at least in part, the early gulf in momentum that divided the teams and enabled the home side to reach the break 31-6 to the good. Beattie claimed the opening try from one of Barkley's sophisticated cross-kicks; Maddock scored the second from close range. Bristol might have been in closer touch had the freakishly rapid Lemi finished either of the two chances that fell to him, but all things considered, they were not in the ball game.
After the half-time team talks - "Mine obviously went down a storm," lamented Ashton - there was a change of emphasis. Roy Winters and Darren Crompton, back from their yellow-card penances, made up for their misdemeanours by putting the squeeze on the Bath forwards; Lemi finally made it over the line after winning a foot race in pursuit of a loose ball; Jason Strange hit the spot with his kicks at goal.
But there was no great likelihood of a Bristol victory, despite the huge swathes of time they spent in opposition territory. They left the Rec chastened, but with their Premiership status intact. Bath have other battles to concern them.
Bath: Tries Beattie, Maddock, Fea'unati; Conversions Barkley 2; Penalties Barkley 4. Bristol: Try Lemi; Conversion Strange. Penalties Strange 3.
Bath: J Maddock; A Higgins, A Crockett, S Finau (M Stephenson, 49), D Bory; O Barkley, N Walshe (A Williams, 58); D Barnes (D Bell, 59), L Mears (P Dixon, 75), T Filise (Barnes, 72), S Borthwick (capt), D Grewcock, A Beattie, M Lipman, I Fea'unati (G Delve, 53).
Bristol: V Going; L Robinson (M Denney, 80), R Higgitt, S Cox, D Lemi; J Strange (D Gray, 76), S Perry; D Hilton (M Irish, 76), M Regan (N Clark, 76), D Crompton, N Budgett (R Winters, 16), G Llewellyn (M Sambucetti, 40), M Salter (capt), J El Abd, D Ward-Smith (G Lewis, 68).
Referee: D Pearson (Northumberland).