The Spanish striker made no mistake from the penalty spot early in the second half after Dean Moxey had handled a cross from Aaron Lennon inside the area. Soldado sent Julian Speroni the wrong way to claim his first competitive goal in a Tottenham shirt and give Andre Villas-Boas' side the perfect start to the season.
As well as Soldado, the Tottenham boss named two of his other new signings - Nacer Chadli and Paulinho - in the starting lineup, while Etienne Capoue had to settle for a place on the substitutes bench.
Marouane Chamakh, signed from Arsenal a week ago, was not deemed fit enough to start by Palace boss Ian Holloway, so he was named on the bench, with new signings Dwight Gayle and Stephen Dobbie given the job of leading the line alongside Aaron Wilbraham.
A frantic opening 10 minutes saw chances at a premium, and when the first serious effort arrived in the 13th minute, the frame of the goal denied Mousa Dembele. Aaron Lennon combined neatly with the Belgian, but his 25-yard strike clipped the top of the crossbar on its way over.
Gylfi Sigurdsson brought the first save from Julian Speroni in the closing 10 minutes of the half with Lennon again involved, as he found the Iceland international on the edge of the penalty area with his back to goal. He turned away from the Palace defense, but his right-footed shot was well tipped over by the Palace goalkeeper.
After a frustrating opening period the visitors broke the deadlock early in the second half after Moxey's handball was punished by referee Mark Clattenburg. Soldado immediately collected the ball and confidently converted the spot kick to get his Spurs career off to a scoring start.
The visitors should have doubled their lead in the 69th minute after excellent build-up play between Kyle Walker and Soldado. The England fullback rolled a perfect pass into the Spaniard’s stride, and his pull back to Sigurdsson gave the Iceland man a clear sight of goal, but he dragged his shot wide.
Chamakh and Kevin Phillips were both introduced late in the game by the hosts, but neither was able to find a way through a resolute Tottenham defense, and Kagisho Dikgacoi was denied by superbly by an onrushing Hugo Lloris in the dying embers to preserve Spurs' three points.