Fernandez-Castano had four birdies, including at the par-3 eighth hole, in building a 4-up lead. He was still up by four after 11 holes but Donaldson won three holes over Nos. 12-16 to get within one.
After both players rang up pars at the par 3 17th, Fernandez-Castano matched Donaldson's birdie at the par-4 18th to win the match.
Thongchai Jaidee won three of his last four holes to close out Ian Poulter in an see-saw 3-and-2 decision. Poulter was up two after three holes and had birdie at the eighth and 12th holes to get back to all-square before Jaidee's run.
Graeme McDowell posted a 5-and-3 win over Chris Wood while Carl Pettersson defeated Thorbjorn Olesen 4-and-3. Francesco Molinari was a 2-and-1 winner over Henrik Stenson and Branden Grace defeated Nicolas Colsaerts 4-and-3. Also, Peter Hanson came away with a 2-and-1 win over George Coetzee.