Somerset must win their final two Twenty20 Cup group matches and hope other results go their way if they are to qualify for the last eight.
That's after Tuesday's four wicket defeat against Midlands, Wales and West Division leaders Warwickshire at Edgbaston.
Justin Langer top scored with 44 from 22 balls, while Arul Suppiah (32) and Omari Banks (32) shared an unbroken stand of 66 as Somerset posted 173-6.
In reply, Jonathan Trott (48) and Jim Troughton (57 from 30) put on 89 for the second wicket to set Warwickshire on their way.
And, despite a late wobble, the hosts sneaked home with four wickets and two balls remaining.
Somerset have now lost all seven Twenty20 Cup meetings between the two sides.
Somerset's remaining games are both away, against Northamptonshire on Thursday and Gloucestershire on Friday.