Goals from Julio Arca, Kevin Kyle and substitute Marcus Stewart gave Sunderland the perfect warm-up for their FA Cup quarter-final against Sheffield United on Sunday.
They controlled the game for long spells against a Walsall side who are now facing a massive battle to avoid relegation.
Walsall have now lost their last three games and failed to win any of their previous nine league matches.
You have to go back to the game at Cardiff City on Boxing Day for their last win.
Neil Emblen had briefly given them hope with a 53rd minute equaliser but they were only back on level terms for just 60 seconds.
Arca gave a sign of what was to come for Walsall when he struck after 18 minutes.
He started the move that led to his sixth goal of the season when he raced forward to the edge of the Walsall area.
He fed a pass into the path of Tommy Smith who saw his shot charged down. Unfortunately for Walsall the loose ball ran to the unmarked Arca who drilled a left-footed drive past the outstretched hand of goalkeeper James Walker.
Arca then showed his value at the opposite end of the pitch five minutes after he had broken the deadlock. A deflected cross from Zigor Aranalde flew over 'keeper MartPoom but Arca was perfectly positioned to head the ball off the line.
Walsall were fired up at the start of the second-half and that determination paid off eight minutes after the re-start.
Sunderland failed to fully clear a corner from Simon Osborn and when Pedro Matias forced the ball back into the area Emblen headed home from six yards.
But Walsall were still celebrating that goal when Kyle pounced to effectively end their challenge 60 seconds later. He headed a cross by John Oster past Walker from 10 yards for his 11th goal of the season.
Leading scorer Stewart then set the seal on Sunderland's success nine minutes from time - and just four minutes after being sent on. He stabbed the ball home at the far post for his 12th goal of the season after Kyle had flicked on a corner from Jason McAteer.