Exeter Chiefs lead London Irish by eight points at the half-time interval thanks to tries from Phil Dollman and Luke Arscott.
The Chiefs took the lead, in their Aviva Premiership match at the Madejski Stadium, in the opening three minutes when, following an Irish clearance they moved the ball through a number of hands and sent Dollman over in the left hand corner.
Gareth Steenson missed the conversion, but added two penalties inside the opening quarter of an hour to give the Chiefs an 11-point advantage.
Irish hit back with a penalty from Ian Humphreys, but Steenson added one of his own to restore the Chiefs' lead.
Then on 18 minutes good work from Matt Jess saw Arscott barrell his way over for a try, which was converted by Steenson.
The rest of the half was dominated by both sides kicking for territory. Humphreys added another penalty for Irish, who were then awarded a penalty try ten minutes before the break, which was converted by Humphreys.
It left Irish trailing 13-21 at the break.