This really was a game of two halves. Bath dominated the fist stanza scoring five good tries to go in 33-10 ahead at the break.
Irish dominated territory and possession in the second half and scored eight points to claim some consolation from the occasion.
The Exiles knew they were going to be in for a forward battle in the week leading up to today’s match and that was the order of the day as George Ford opted to kick the ball to the corner as the home side were awarded their first penalty.
Bath had the upper hand in the close quarters and after winning good lineout ball, the ball was spun wide to Jonathan Joseph who dotted down after six minutes.
Shane Geraghty, who was a late replacement for Ian Humphreys, got Irish on their way with a penalty goal on 11 minutes after good work at the breakdown by the Irish forwards.
Geraghty’s penalty only halted the home side’s progress as Guy Mercer crossed for the first of his two tries on 22 minutes. Topsy Ojo tried to usher the ball over the touchline on his five metre line, but unfortunately had the last touch. George Ford took a quick lineout to Guy Mercer who dived over the line. Irish protests were in vain as the assistant referee judged the ball to have touched Ojo before it crossed the touchline.
George Ford scored an individual try on the half hour mark after evading three Irish tacklers. Referee, Luke Pearce, went up to the TMO who confirmed the Bath fly half had dotted the ball down.
Things went from bad to worse for Irish as first Rob Webber was driven over by the Bath pack and then Guy Mercer crossed fior his second try to give his side an unassailable lead.
Shane Geraghty scored a great individual try just before the break to finish off a decent first half for the fly half.
The second half was a different story. Irish were physical, determined and reaped the rewards. Geraghty kicked a penalty two minutes within the re-start to get the ball rolling after great work from replacement front rowers John Yapp and Jamie Hagan.
The former England international kept creating opportunities with his attacking endeavour and after Alex Lewington grubber kicked the ball up the touchline, Geraghty was able to latch on and dot down.
Neither side troubled the scoreboard for the remaining 11 minutes as Bath ran out 33-18 victors.
Irish welcome Harlequins to Madejski Stadium next week for round five of the Aviva Premiership.
Score sequence (London Irish first): 0-7; 3-7, 3-14, 3-21, 3-26, 10-26, 10-33, 13-33, 18-33
Scorers: Bath Rugby: Tries: Joseph (6), Mercer (22, 38), Ford (30), Webber (34); Conversions: Ford (4); London Irish: Penalties: Geraghty (11, 42); Tries: Geraghty (36, 69); Conversions: Geraghty
15. Anthony Watson (rep: Ollie Devoto, 17); 14. Semesa Rokoduguni; 13. Jonathan Joseph; 12. Kyle Eastmond (rep: Tom Biggs, 74); 11. Matt Banahan; 10. George Ford; 9. Peter Stringer (rep: Martin Roberts, 70); 1. Paul James (rep: Anthony Perenise, 60); 2. Rob Webber (rep: Ross Batty, 67); 3. David Wilson (rep: Kane Palma-Newport, 68); 4. Dominic Day (rep: Alafoti Fa'osiliva, 40); 5. Dave Attwood (Captain) (rep: Hooper, 4); 6. Matt Garvey; 7. Guy Mercer; 8. Leroy Houston
Replacements: 16. Ross Batty; 17. Anthony Perenise; 18. Kane Palma-Newport; 19. Stuart Hooper; 20. Alafoti Fa'osiliva; 21. Martin Roberts; 22. Ollie Devoto; 23. Tom Biggs
15. Topsy Ojo (rep: Leo Halavatau, 60-68); 14. Marland Yarde; 13.Fergus Mulchrone (rep: Jimmy Stevens, 42-50); 12. Eamonn Sheridan; 11. Alex Lewington; 10. Shane Geraghty; 9. Tomás O’Leary (Captain) (rep: Darren Allinson, 68); 1. Matt Parr (rep: John Yapp, 40); 2. David Paice; 3. Leo Halavatau (rep: Jamie Hagan, 40); 4. Nic Rouse (rep: Bryn Evans, 52); 5. Jebb Sinclair (rep: Ian Gough, 52); 6. Declan Danaher (rep: Blair Cowan, 40); 7. Kieran Low; 8. Ofisa Treviranus
Replacements: 16. Jimmy Stevens; 17 John Yapp; 18. Jamie Hagan; 19.Ian Gough; 20. Bryn Evans; 21. Blair Cowan; 22. Myles Dorrian; 23. Darren Allinson
Referee: Luke Pearce