An extraordinary chapter in South Island racing has closed with the retirement of El Chico.

The 12-year-old ended his lengthy and successful career with his fourth placing in the open sprint at Ashburton on Thursday.

"He's been a lovely horse to work with and you can't always say that about the good ones," said part-owner Michael Pitman, who trained El Chico with his son Matthew.

"I've never had any issues with him and he's won every season since 2008.

"He's always tried his best and this preparation he only struck a firm track once. Even at Ashburton, Chris Johnson was adamant that he would have won on a better track."

El Chico was a six race winner when Pitman purchased the son of Stravinsky and he admitted that he didn't envisage the horse winning a further 18 races for them.

"I bought him for a modest sum as a five-year-old, thinking he would be a country cups' horse.

"He's won $667,000 and basically $600,000 of that as a South Island horse."

Pitman singled out El Chico 's win in last year's Gr.3 Stewards' Stakes, his second success in the contest, at odds of $45-1 as a career highlight.

"I was very confident and told everyone to back him - he had worked so well before the race," he said.

El Chico also won the Gr.3 Easter Cup, the Listed Timaru Stakes three times and the Listed Timaru Cup. He also finished third in the 2012 Gr.1 Telegraph Handicap.

"He's been a great horse and he enjoys stable life so he'll be staying here with us," Pitman said.