Polland produced a dramatic fightback as he came from three down after three holes to defeat Spain’s Antonio Garrido three and two and then watched as O’Sullivan booked his place in the semi-finals with a similar victory over England’s Denis Durnian.
The other semi-final will pitch Jamaica’s Delroy Cambridge against England’s Nick Job.
Cambridge produced some superb golf to end the challenge of England’s Brian Evans, the club professional at Pinheiros Altos in Portugal, while Job crushed Scotland’s Mike Miller four and three in a lopsided quarter-final.
Polland, the 1975 Sun Alliance PGA Match Play champion, lost the first three holes but then started his recovery in glorious fashion when he hit a drive and a two iron to three feet for a winning eagle on the 495-yard par-five sixth.
He won five successive holes from the eighth to go three up and then finished the job with a birdie on the 14th and then his second eagle of the day on the par-five 15th.
‘‘When we started I thought I was in for an early bath,’’ said Polland, who lives in nearby Sotogrande. ‘‘But, once I warmed up, I hit a lot of good shots. I am very pleased with my game.’’
O’Sullivan also came from behind to defeat Durnian in an excellent encounter between two great friends.
The former Irish Amateur champion, who represented his country in eight home internationals and four European Championships, lost the third and the fifth before starting his comeback with a birdie in the 495-yard par-five fifth.