An own goal and two smart finishes condemned City to a 3-0 defeat in the capital at Charlton Athletic.
City fell behind to a free-kick deflecting off Angus MacDonald and in midway through the first half, before the Addicks then doubled their lead through a good Tyreece Campbell finish from the edge of the box.
Substitute Miles Leaburn then sealed the three points for the home side, drilling a in low inside the six-yard box with just a few minutes remaining.
For this trip to the capital, Gary Caldwell made two changes from last week's win against Cambridge. Jake Richards returned in the centre of midfield while Demetri Mitchell was also included from the start. A late injury to Shaun MacDonald meant that City didn't name a backup keeper on the bench.
First half
The offside flag halted the game’s first attack, though it would have been inconsequential anyway, as Tyreece Campbell fired well wide for the hosts inside the opening two minutes.
Charlton looked to pin City back early on, dictating possession, but they found a composed Grecians defense that withstood the initial pressure. Exeter then registered their first effort through Ryan Trevitt, though his long-range strike was well off target.
The Grecians grew into the game from there and won a free-kick 30 yards out on the left after Joel Cowlill was fouled. Trevitt tried his luck again - this time on target - but his effort was comfortably saved by Will Mannion in goal for the Addicks.
Despite looking like they were making ground in this fixture, City fell behind in the 20th minute.
A clumsy challenge conceded a free-kick wide on the right of Exeter’s penalty area, and Luke Berry stepped up. Whipping the ball low into the box, it took a deflection off Angus MacDonald, nicking past Joe Whitworth and into the net.
Charlton then began to pile on the pressure, with MacDonald and Whitworth both making crucial blocks to deny fiercely struck efforts from Campbell at a tight angle.
Unhappy with his team’s performance, Gary Caldwell made a rare unenforced first-half substitution, bringing on Ryan Woods for Ilmari Niskanen. The change prompted a shift in shape, which helped City settle, but while they managed to hold off Charlton’s attacks, they struggled to create much at the other end.
Second half
Caldwell made another change at the break, bringing on Tony Yogane for Jake Richards, but again it was Charlton who made the first attack.
Karoy Anderson struck the ball low from close range after being found by a cut-back into the box, but Whitworth made an excellent reactionary block, before the Palace loanee pounced on Matt Godden's follow-up.
Anderson had another chance in the 57th minute when he met a cross from the right unchallenged, but fortunately for City, his header drifted wide of the mark.
The Grecians kept plugging away, but it was the home side who doubled their lead in the 68th minute.
Hartridge’s header was intercepted by Tyreece Campbell, who picked his spot from the edge of the box before placing a precise shot into the bottom corner, well out of Whitworth’s reach.
City's loss was compounded six minutes from time, when Miles Leaburn rounded off Charlton's win. After waltzing through the Grecians' defence, he struck hard and low from the top corner of the six-yard box in.
A few half chances came Exeter's way in the game's closing minutes, but nothing was made of them, as the Addicks' three goals won all three points at the Valley.
Charlton Athletic: Mannion, Ramsay, Gillesphey, Jones (C), Coventry (McIntyre, 86'), Campbell (Kanu, 86'), Berry (Gilbert, 75'), Edwards (Watson, 89'), Anderson, Godden (Leaburn, 75'), Small.
Substitutes not used: Reid (GK), Aneke.
Goals: MacDonald (OG) 20', Campbell 67', Leaburn 84'
Exeter City: Whitworth, Niskanen (Woods, 33'), McMillan, MacDonald, Hartridge, Harper, Richards (Yogane, 46'), Trevitt (Jones, 78'), Colwill (Oluwabori, 78'), Mitchell (Cole, 63'), Magennis (C).
Substitutes not used: Purrington, Francis.
Yellow cards: Niskanen 19', Mitchell 51', Colwill 55'
Attendance: 14864 (1247 away)