The Saddlers suffered a second successive 1-0 home defeat at the hands of ten-man Gillingham.
Conor Wilkinson scored the only goal just before half-time after pouncing on Liam Kinsella’s short back-pass.
The result leaves Walsall in 18th place.
The hosts started brightly and could have taken a 12th-minute lead when Kieron Morris’ close-range effort from Erhun Oztumer’s corner was brilliantly kept out by the left leg of keeper Tomas Holy.
Zeli Ismail was in the thick of the action, combining well with Oztumer before delivering a menacing right-wing cross which a diving Holy palmed away.
Amadou Bakayoko and Kieron Morris each dragged efforts wide from long range, while the latter also fired straight at Holy after collecting Ismail’s wonderful crossfield pass.
The lively Ismail tried his luck himself on the half-hour, hitting a left-footed drive from 20 yards which Holy held comfortably.
Despite dominating the first half, the Saddlers fell behind on the stroke of half-time.
After Luke Leahy had conceded possession, Tom Eaves skipped past Jon Guthrie on the right and delivered a low cross which Liam Kinsella attempted to cushion back to his keeper.
But the defender badly under-hit his back-pass, with Conor Wilkinson nipping in to prod past the advancing Liam Roberts and give Gillingham a 44th-minute lead.
Walsall began the second period purposefully, with Morris drilling a fierce low strike wide of the far post via a deflection.
Amadou Bakayoko had two good chances to draw the Saddlers level just before the hour mark.
The Sierra Leone-born striker first played a neat one-two with Adam Chambers before seeing his powerful, rising drive expertly tipped over by Holy at his near pot.
Luke Leahy then threaded a pass through to Bakayoko, who blazed badly wide when he should have done better.
Moments later, boss Jon Whitney made a double switch, bringing on Tyler Roberts and Reece Flanagan for Joe Edwards and Morris.
Tyler Roberts very nearly created an equalising goal midway through half, swinging in a teasing cross but a stretching Oztumer couldn’t quite connect.
The Gills were reduced to ten men on 72 minutes when Max Ehmer was shown red for two bookable offences.
With a man advantage, the Saddlers laid siege on the visitors’ goal, seeing several attempts blocked.
On 86 minutes, Flanagan rolled a pass into the feet of substitute Dan Agyei, who rolled his man superbly before shooting straight at Holy.
Gillingham could have made it 2-0 deep in stoppage time but Scott Wagstaff’s rasping drive from a swift counter-attack was parried by Liam Roberts.
Team: L Roberts, Kinsella, Guthrie, K Roberts, Leahy, Chambers, Edwards (T Roberts 60’), Morris (Flanagan 60’), Ismail, Oztumer, Bakayoko (Agyei 70’).
Subs not used: Gillespie, Devlin, Donnellan, Kouhyar.
Attendance: 4,917 (355 Gillingham supporters).