Exeter recorded their first away win of the Aviva Premiership season after beating London Irish 27-23 at the Madejski Stadium.
The Chiefs 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.
The Chiefs made the perfect start and within five minutes they were in front, as the ball was worked wide into the hands of Phil Dolman, who crossed for an unconverted try.
Minutes later Gareth Steenson put eight points between the two teams with his first penalty of the afternoon, and it was 0-11 when he added a second shortly after.
The Exiles got off the mark courtesy of an Ian Humphreys three-pointer, though the 11-point cushion was quickly restored by the boot of Steenson.
Exeter then went further ahead at the end of the first quarter when Luke Arscott rampaged over the tryline following strong work from Matt Jess.
Steenson was this time on target with the conversion to make it 3-21, though a Humphreys penalty and the hosts' first try, scored by Leo Halavatu, meant there were just eight points between the two teams at the interval.
There were fewer points scored in the second half, but no shortage of drama as London Irish turned the game on its head with a converted try and penalty within ten minutes of the restart.
Topsy Ojo got on the end of a clever Humphreys chip to touch down, before Humphreys' conversion and penalty completed the comeback, making it 23-21.
But indiscipline cost the hosts their lead almost immediately, as Steenson knocked over another three points to put his side back in front.
Irish searched for a response in the minutes that followed but the Chiefs' defence and discipline held firm and, when hit his fifth three-pointer of the afternoon in the dying minutes, the win was sealed.
For London Irish:
Tries: Halavatau, Ojo
Cons: Humphreys 2
Pens: Humphreys 3
Tries: Arscott, Dollman
Pens: Steenson 5
London Irish: 15 Tom Homer, 14 Topsy Ojo, 13 Sailosi Tagicakibau, 12 Shane Geraghty, 11 Anthony Watson, 10 Ian Humphreys, 9 Darren Allinson, 8 Chris Hala'ufia, 7 Jamie Gibson, 6 Declan Danaher (c), 5 Bryn Evans, 4 Matt Garvey, 3 Leo Halavatau, 2 Brian Blaney, 1 Max Lahiff.
Replacements 16 Gerard Ellis 17 Richard Palframan, 18 Cai Griffiths, 19 Kieran Low, 20 Alex Gray, 21 Conor Gaston, 22 Steven Shingler, 23 Jack Moates.
Exeter Chiefs: 15 Luke Arscott, 14 Jack Nowell, 13 Phil Dollman, 12 Jason Shoemark, 11 Matt Jess, 10 Gareth Steenson, 9 Haydn Thomas, 8 Richard Baxter, 7 James Scaysbrook, 6 Dean Mumm, 5 James Hanks, Tom Hayes (c), 3 Carl Rimmer, 2 Chris Whitehead, 1 Brett Sturgess.
Replacements 16 Simon Alcott, 17 Ben Moon, 18 Hoani Tui, 19 Aly Muldowney, 20 Tom Johnson, 21 Kevin Barrett, 22 Ignacio Mieres, 23 Sireli Naqelevuki.