Bath showed their Aviva Premiership title credentials on Saturday thanks to a gutsy 20-13 win over London Irish, who had George Stowers sent off.
Nick Abendanon scored an injury-time try as Bath thwarted their rivals after an exhausting contest littered with injuries at the Recreation Ground.
Bath saw four of their star-studded squad - internationals Matt Banahan, Lee Mears, David Flatman and Simon Taylor - make premature exits along with Irish's England flanker Steffon Armitage.
And there was an early demise for Irish's Samoan number eight George Stowers, who was sent-off for a high tackle on Bath full-back Abendanon.
Abendanon appeared to be briefly knocked out in the 65th-minute incident before Stowers - who collected a three-week ban for fighting with ex-Gloucester captain Gareth Delve last season - received his marching orders.
Bath centre Olly Barkley - a summer discard from England boss Martin Johnson's elite player squad - stayed standing to kick five penalties and give Bath their second successive Premiership win this term.
Barkley, seemingly intent on making a mockery of Johnson's decision in front of his fellow England coaches Brian Smith and John Wells, was also at the heart of Bath's more creative moments, although neither side could break each other down until the closing minutes.
Irish, against the odds, went ahead when their impressive young wing Jonathan Joseph crossed after 78 minutes, and fly-half Ryan Glam, who kicked two first-half penalties, slotted the conversion to threaten a famous Irish victory.
But Bath responded immediately when scrum-half Michael Classens kicked expertly into space and Abendanon finished with a flourish before Barkley slotted his fifth penalty with the game's final kick.
Lamb and Barkley exchanged penalties inside the opening five minutes, but the game quickly became a tale of dominant defences as both teams strived for an attacking spark.
Banahan made a clean midfield break midway through the first half, almost freeing Bath's England captain Lewis Moody in the process yet it was to be his final contribution as Banahan limped off following a crunching tackle.
And Banahan was soon joined in the casualty department by his fellow England internationals Mears and Armitage, who also failed to last the opening 25 minutes of an encounter played at lightening-fast pace in glorious sunshine.
Bath hooker Mears appeared to suffer a wrist problem, while Armitage hobbled gingerly away from the action and it was the home side who continued to control territory even though that was not readily apparent on the scoreboard.
A second Barkley penalty nine minutes before half-time nudged Bath ahead, only for Irish to underline their attacking prowess when full-back Delon Armitage beat several players during a weaving run that stretched the home side's defensive organisation.
Bath's response saw substitute Tom Biggs, on for Banahan, sprint towards the left-hand corner yet Irish snuffed out any danger, being partially helped by Abendanon delivering his pass to Biggs too early.
Bath lost a third injured player on the stroke of half-time, Scotland's Taylor being replaced by Andy Beattie, but Barkley continued to hit the target by completing his penalty hat-trick before Lamb reduced the arrears to 9-6 at the break.
The hosts, after losing Banahan, Mears and Taylor in quick succession, regrouped impressively to keep Irish at a safe distance before Flatman became their fourth injury victim.
Bath unlocked the Irish defence after 51 minutes but scrum-half Classens's clever reverse pass to Abendanon was ruled forward by referee Dave Pearson and Irish enjoyed a reprieve.
They didn't help their case though, when Irish's former Bath back Elvis Seveali'i was sin-binned for a dangerous tackle on home fly-half Sam Vesty and Pearson immediately reached for the yellow card.
Barkley immediately punished Irish by stroking over his fourth successful penalty and the 14-man visitors knew they had to keep their shape and composure as Bath pressed to make the game safe.
Irish were forced into some frantic defensive work, especially after Stowers' exit yet their numerical disadvantage counted for little when Joseph sprinted in at the corner.
Bath were suddenly in danger of losing a match they had controlled for so long, but Abendanon's late intervention secured the victory and left Irish to head back down the motorway with just a losing bonus point.
Pen: Barkley 5
For London Irish:
Pen: Lamb 2
Red card: George Stowers (London Irish - 62 minutes)
Bath: 15 Nick Abendanon, 14 Matt Carraro, 13 Shontayne Hape, 12 Olly Barkley, 11 Matt Banahan, 10 Sam Vesty, 9 Michael Claassens, 8 Luke Watson (capt), 7 Lewis Moody, 6 Simon Taylor, 5 Danny Grewcock, 4 Stuart Hooper, 3 David Wilson, 2 Lee Mears, 1 David Flatman.
Replacements: 16 Pieter Dixon, 17 Nathan Catt, 18 Duncan Bell, 19Ben Skirving, 20 Andy Beattie, 21 Mark McMillan, 22 Tom Biggs, 23 Jack Cuthbert.
London Irish: 15 Delon Armitage, 14 Topsy Ojo, 13 Elvis Seveali'i, 12 Daniel Bowden, 11 Sailosi Tagicakibau, 10 Ryan Lamb, 9 Paul Hodgson, 8 George Stowers, 7 Steffon Armitage, 6 Declan Danaher, 5 Bob Casey, 4 Kieran Roche, 3 Faan Rautenbach, 2 David Paice, 1 Clarke Dermody (capt).
Replacements: 16 James Buckland, 17 Max Lahiff, 18 Alex Corbisiero, 19 Nick Kennedy, 20 Matt Garvey, 21 Seilala Mapusua, 22 Jonathon Joseph, 23 Chris Malone.
Referee: Andrew Small