Both shot four-under-par 67s in harsh conditions, along with the local hope Rolf Muntz, Spain's Ignacio Garrido and the Italian Emanuele Canonica.
Romero, who missed the cut at Carnoustie last week, was the first of the Cordoba duo to post his score, finishing with birdies on the final two holes. Cabrera was fourth in last week's Open and confirmed his liking for difficult golf when he added a late birdie to two eagles.
After two second-place finishes in the Benson and Hedges International and Irish Open this season to go with his fine Open showing, Cabrera is the highest-placed European Order of Merit player competing.
Romero is not alone in thinking Cabrera's time is nigh. "I think he'll win his first event pretty soon," said Romero. "He's won 10 or 12 tournaments in South America and I thought it was about time he tried his hand in Europe and I think it's great he's proving me right."
After failing at three European qualifying schools from 1992, Cabrera finally made it on to the tour in 1995. "I'm learning all the time and I just know a title will come if I stay patient," said Cabrera, who finished just one shot off the play-off at Carnoustie. "The experience at Carnoustie will stand me in good stead for the rest of my life - never give up on anything. I might have won a major."
The favourites, Jose Maria Olazabal and Lee Westwood, both trailed the leading quintet. Olazabal struggled to a 74, while Westwood bogeyed two of the last five holes for a 72.
England's David Howell chances of making the Ryder Cup team suffered a blow when he had to retire with an infected toenail after a few shots. Howell is 15th on the table and time is running out with just four qualifying tournaments remaining.Reuse content