Ballesteros' compatriots Miguel Angel Jiménez and José Maria Olazábal led the tributes at Real Club de Golf El Prat, the pair competing in the third round despite their grief.
"He was outstanding for his determination and his passion in everything he did," said Jiménez. "He never gave up, he always found a way out, and this was reflected in his personality."
Olazábal, who formed a formidable Ryder Cup partnership with Ballesteros, added: "What impressed most in Seve was his strength, his fighting spirit and the passion he put into everything he did."
On the course Aiken parred his first four holes to remain eight under, one ahead of Spaniard Pablo Larrazábal, who recovered from an opening bogey with a birdie from five feet at the fourth.
France's Gregory Havret was making the biggest move of the day, four birdies in his first seven holes and a further gain at the 14th taking him to five under for the day and six under overall to share third with Anthony Wall.
A minutes silence in memory of five-time Major winner Ballesteros was due to be held at 1445.
Aiken bogeyed the sixth, but after a birdie on the next and two pars he turned in front of France's Romain Wattel and Spaniard Larrazábal, dressed all in black.