Exeter recorded their first away win of the Aviva Premiership season with a remarkable 27-23 victory over London Irish at the Madejski Stadium.
Exeter were leading 21-3 after just 18 minutes and the hosts looked in grave danger of being routed, but the Exiles rallied to build a 23-21 lead midway through the second half.
It fell to Gareth Steenson to score two late penalties and earn victory for Exeter.
Phil Dollman and Luke Arscott scored tries for the Chiefs with Steenson kicking three penalties and a conversion as the Chiefs appeared to be coasting.
Ian Humphreys booted three penalties and two conversions for the Exiles in addition to tries from Leo Halavatau and Topsy Ojo.