New South Wales had clinched the series with victories in games one and two but the Maroons rallied in the 'dead rubber' to restore some pride, to the delight of the 51,214 crowd at Brisbane's Suncorp Stadium.
Slater, who captained his state on his 31st and final appearance, was named man of the series while scrum-half Daly Cherry-Evans made an impressive, tryscoring return to the Maroons side and winger Valentine Holmes contributed all but four of his team's points with two tries and three goals.
After Slater had an early try disallowed for a knock-on, Holmes opened the scoring in the 12th minute after intercepting a James Tedesco pass and sprinting 90 metres for his first try.
Holmes kicked the conversion and added a penalty to make it 8-0 after Blues half-back James Maloney was sin-binned for an obstruction on Slater.
Queensland ought to have been further in front, especially after forcing four goal-line drop-outs in quick succession, but the Blues stunned the home crowd by taking the lead while down to 12 men with two tries in the closing stages of the first half.
Winger Tom Trbjovevic replicated Holmes' interception score while full-back Tedesco took hooker Damien Cook's pass to go over from close range and, with Nathan Clearly kicking both goals, Brad Fittler's men suddenly had their sights on a first clean sweep for 18 years.
However, Holmes grabbed his second try 11 minutes into the second half to bring the scores level and stand-off Cameron Munster came up with a decisive break for Cherry-Evans to over six minutes later to restore Queensland's lead.
Holmes kicked his third goal to wrap up the scoring and pulled off a crucial interception in the dying moments to clinch a breathtaking victory.
"They're a tough side," Slater said. "I'm really happy for our boys, we just had to keep turning up,"
