Brentford booked their place the FA Cup Third Round as an early Leon Legge goal was enough to see off Walsall.
The central defender powerfully headed home a John Bostock corner 13 minutes in to the Second Round tie and although both teams will feel they should have given the encounter a second goal it was not to come.
The Bees, forced to completely re-vamp their back line due to injuries and unavailability of loan signings, produced a fine first half performance and could have had the game sewn up by the break.
As in the league encounter last week - where Brentford also lead at half time - Walsall came back strongly after half time but this time they could not find an equaliser to force a replay.
Overall, The Bees deserved to progress and Walsall could have had no complaints if they had been three down at half time.
Ben Strevens was just unable to turn in a Charlie MacDonald cross and when a long throw was half cleared moments later Mark Hughes had to clear an acrobatic Strevens effort off the line.
The goal came soon after and although Lewis Price saved from Matt Richards soon after Brentford were dominant.
Strevens set Bostock free and with two waiting in the middle his cross was deflected on to the roof of the net.
A Ryan Dickson header from a Bostock corner was headed off the line by Richards and the on-loan Spurs man curled a free kick narrowly over soon after.
MacDonald volleyed over and Sam Wood had a low shot saved before Walsall started to press late in the half.
Price saved from Mark Bradley, Netan Sansara blazed over and Manny Smith headed wide at the far post from a Richards corner.
The early stages of the second half saw Brentford push for the second goal that would all but kill the tie off.
They thought they had won a penalty when Dickson broke forward and saw a shot cannon for a corner off the arm of Smith but nothing was given, and Walsall had similar appeals later on for an alleged offence by Danny Foster but again they were also waved away.
Legge had a header from another Bostock corner saved, as did Dickson soon after, but as the game ticked on Walsall started to throw everything at Brentford in search of the goal that would give them a replay.
Troy Deeney headed a corner wide, Rhys Weston shot over and Alan Bennett diverted another Deeney shot wide after space was created in the left channel before Smith headed wide.
But Walsall left gaps at the back - Strevens had a low shot saved after a run by Bostock, Legge headed narrowly wide and Clayton Ince produced a fine low save to keep out a curling Strevens shot.
Substitute Cleveland Taylor should have made it safe when a Bostock through ball sent him through - he looked set to pull the trigger but the ball got caught up in his feet and Richards made the challenge.
Price saved a looping header from Darren Byfield and it took a brilliant block from Bennett to keep out a Deeney shot while Price saved Sam Parkin's effort from the re-bound.
Taylor was a menace on the right and could have done better when firing a shot well over from 20 yards and then forcing a low save out of Ince.
Deeney headed wide before Legge produced a match-winning tackle when Steve Jones was bearing down on goal.
Substitute Rhys Murphy had an effort from a tight angle saved and as the game ticked into stoppage time Walsall threw more and more bodies forward.
Bradley shot wide from the edge of the box and Price rushed out to save at the feet of Jones.
The Bees defence, with Legge commanding, held firm and Walsall were unable to get the equalising goal.
Brentford: Price; Foster, Bennett, Legge, Dickson; Bostock (sub Murphy 89 mins), Bean, O'Connor, Wood (sub Taylor 72 mins); MacDonald (sub Hunt 84 mins), Strevens
Subs (not used): Moore; Osborne, Saunders, Cort
Walsall: Ince; Weston (sub Westlake 90 mins), Hughes, Smith, Sansara; Jones, Mattis, Bradley, Richards; Deeney, Byfield (sub Parkin 79 mins)
Subs (not used): Gilmartin, Nicholls, O'Keefe, Till, McDonald
Bookings: Mattis (44 mins), Sansara (78 mins), Smith (90 mins)
Attendance: 2,611 (308 away fans)
By Chris Wickham