Wardlaw and Smith were awarded free kicks inside the final 90 seconds but both failed to score as the Saints fell to a 5.6 (36) to 5.5 (35) defeat in Ballarat on Sunday.
After a promising 3-0 start, Nick Dal Santo's side have lost six of their past seven games.
It means they will miss the top eight and are still searching for their first finals appearances after five seasons in the competition.
The Bulldogs are also well out of the hunt for a finals berth this year, but they have registered consecutive victories over the past two rounds after a horror 2-6 start.
Jessica Fitzgerald starred for the Dogs, celebrating her 50-game milestone with 26 disposals, six clearances and two goals.
Captain Deanna Berry also shone with 21 touches and five clearances. She also kicked one of the goals of the season with a brilliant snap from hard up against the boundary line under pressure from two opponents.
Nat Exon and Ashleigh Richards kicked two goals each for St Kilda, who led throughout the first half and stretched their lead to 14 points early in the third quarter.
But the Bulldogs kicked the next three goals and led by one point at the 10-minute mark of the final term through a behind to Heidi Woodley, which was the final score of the game.
Wardlaw (18 disposals, 11 hit-outs) impressed in the ruck and was gifted a chance to win the game through a free kick paid against Alice Edmonds.
She sprayed the shot badly from just inside 50 metres.
St Kilda had one last chance when Elisabeth Georgostathis was penalised for deliberate out of bounds, but Smith put her shot out on the full and the Bulldogs hung on.
Both sides have 4-6 records and will end their seasons with games against finals-bound opponents next Sunday.
St Kilda host Brisbane at RSEA Park, while the Bulldogs travel west to take on Fremantle.
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