Pendleton, 35, had been unseated from the same horse at Fakenham on her National Hunt debut 12 days earlier.
But the double Olympic cycling champion, who has been riding for just over a year, jumped well and led all the way to win by 29 lengths.
A decision on whether she rides in the Foxhunter Chase at the Cheltenham Festival will be made next Monday.
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"I will do some more point-to-points and see what the experts around me decide and I will go with their choice," said Pendleton. "But I will definitely be riding for the rest of the season."
Pendleton, who had come second in a flat race at Ripon last summer, stayed clear of trouble as she made all the running on the Paul Nicholls-trained gelding to comfortably win the hunter chase from the veteran Big Fella Thanks.
5 live In Short: Pendleton on "incredible" first win
She will again partner the nine-year-old Pacha Du Polder if she gets the go-ahead to compete at Cheltenham on 18 March.
Pendleton added: "In cycling, my performance was so monitored. I knew exactly my power output, the speed I'd try to be maintaining - everything was so specific, calculated and planned. When you get on a racehorse, everything else goes out the window.
"I really wanted to get round and give the horse the ride he deserved. I feel honoured to ride such a wonderful horse."
It looks increasingly likely that barely a year after taking up riding, and taking on the challenge of lining up at jump racing's Cheltenham Festival, Victoria Pendleton will contest the Foxhunter Chase.
A much more polished, less nervy performance at windswept Wincanton, leading all the way and never close to being unseated, saw her banish the memory of her recent fall.
No final decision about Cheltenham has been made but the endorsement of Pacha Du Polder's trainer Paul Nicholls that she is now "more than qualified" seems pretty ringing to me.

Jason Nelson, 32, admits killing Jordan Maguire, 20, at his Luton home, in a "spree of violence" on 26 May 2013 but claims it was done in self-defence.
The former resident of Marsh Farm Estate in Luton has pleaded not guilty to murder, rape and sexual assault.
A man who saw Mr Maguire stabbed three times said the accused "showed no regrets or remorse" afterwards.
Luton Crown Court heard the attacks happened at Mr Maguire's home in Thrales Close between 18:00 and 20:15.
The prosecution allege Mr Nelson was in the middle of a spree of violence, having sexually assaulted a 25-year-old woman in the stairway of some flats and then a 60-year-old woman in her flat.
Witness Dennis Kamau said he and his girlfriend were looking to buy some cannabis when he came across Mr Nelson near the Nisa store on the estate.
He took the pair to Mr Maguire's home where the men entered the house while the woman stayed outside.
After the pair agreed to share a deal, they went to the kitchen where Mr Maguire removed a tin from a kitchen cabinet.
Mr Kamau said: "The next thing I saw was a knife rise above and attack Jordan.
"I saw the knife go into Jordan. Jordan acted all shocked. He stabbed him a second time."
Mr Kamau told the jury the victim was then stabbed in the back by Mr Nelson who said "You little pussy" before putting the knife away and riding off on his bike.
"I was scared, terrified and shocked," said Mr Kamau.
Asked how the accused appeared, he said: "He showed no regrets or remorse."
A stab wound to the chest had punctured Mr Maguire's aorta and he was fatally injured.
The jury earlier heard Mr Nelson stayed for two weeks with a girlfriend in Ipswich before flying to his native Grenada and was later arrested in Trinidad.
Victoria Pendleton won her first race as an amateur jockey on 5-4 favourite Pacha Du Polder at Wincanton.
[NEXT_CONCEPT]
A man who stabbed a drug dealer to death showed no remorse after the knife went in, a jury has heard.