Following his stage victory in the Volta ao Algarve on Thursday, Dan Martin started Friday's 18 kilometre time trial hoping to ride strongly but was unable to defend his race lead against the clock.
The Irish QuickStep Floors rider finished one minute 40 seconds behind the winner Jonathan Castroviejo (Movistar), and one minute 35 behind the rider who had finished second to him on Thursday, Primoz Roglic (LottoNL-Jumbo).
Roglic duly took over at the top of the general classification, with Martin dropping to sixth overall, one minute 31 seconds back.
Best of the Irish was Ryan Mullen (Cannondale-Drapac), who was a fine 14th. He was just 35 seconds behind the stage winner and may well have contended for the victory had he not had mechanical problems early on in the test.
The race continues until Sunday.