The Saddlers’ six-match winning home run came to an end after a narrow defeat against second-placed Fleetwood.
Cian Bolger scored the game’s only goal midway through the first half when he headed home Cameron Brannagan’s corner.
The Cod Army could have won more comfortably, with Elohor Godswill heading against the bar and Neil Etheridge making a stunning save to deny Brannagan.
Scott Laird and Erhun Oztumer went closest for Jon Whitney’s men, who remain in ninth position.
Walsall entered the match hoping to equal a Banks’s Stadium record of seven successive league victories - a feat only achieved once before, back in 2006.
And it was the hosts who threatened first with captain Adam Chambers having a speculative long-range effort deflected wide.
Fleetwood, beaten for the first time in 19 matches on Saturday, responded with Ben Davies meeting Brannagan’s delivery with a glancing header which Isaiah Osbourne cleared off the line.
Uwe Rosler’s promotion-chasers took the lead midway through the half, Bolger rising highest to power a well-placed downward header beyond Neil Etheridge from Brannagan’s left-wing corner.
Walsall immediately sprang into life, with Erhun Oztumer spinning away from his man before firing over from distance and Scott Laird dragging a left-footed effort wide after a scramble in the box.
But the Saddlers were indebted to keeper Etheridge for not falling two behind on the half-hour.
Jon McLaughlin’s low cross arrived with Brannagan at the back post but the Liverpool loanee’s curling attempt was brilliantly kept out by a diving Etheridge from close range.
The hosts suffered an injury blow shortly after as Celtic loanee Eoghan O’Connell was forced off with what appeared to be a hamstring problem, being replaced by Matt Preston.
The visitors were looking particularly dangerous from dead balls and almost grabbed another set-piece goal on the stroke of half-time.
A Brannagan free-kick was nodded back across goal by Bolger and headed onto the bar by Elohor Godswill, with Kyle Dempsey’s follow-up cleared superbly off the line by Chambers.
Half-time: Walsall 0-1 Fleetwood
The Cod Army continued to do most of the pressing after the interval. Brannagan’s whipped free-kick curled just wide and Ash Hunter’s well-struck 25-yarder was parried by Etheridge low to his left.
With Walsall making little headway going forward, manager Jon Whitney turned to his bench and brought on Amadou Bakayoko and Andreas Makris in place of Simeon Jackson and George Dobson.
But still the Saddlers found scoring opportunities hard to come by.
Joe Edwards cut into the box before hitting a right-footed shot which deflected wide before his deep corner was headed over by Preston.
The closest the hosts came to finding an equaliser was in the final minute of normal time, Oztumer curling a 25-yard free-kick over the wall but wide of Alex Cairns’ right-hand upright.
Full-time: Walsall 0-1 Fleetwood
Team: Etheridge, Preston, O’Connor, O’Connell (Preston 36’), McCarthy, Chambers, Osbourne, Dobson (Makris 73’), Edwards, Oztumer, Jackson (Bakayoko 68’).
Subs not used: MacGillivray, Morris, Randall, Moussa.
Attendance: 3,890 (142 Fleetwood supporters).