Doug Harrison has long believed Lopartega has the makings of a middle-distance mare and the trainer will stretch her beyond 1600m for just the second time at Flemington.

Lopartega meets her last-start conqueror Hell Or Highwater again in Saturday's Hollywood Nails Handicap (1700m) when she steps up in distance from her last-start second over 1600m at Moonee Valley.

"She has always given us the indication she would make into a lovely 2000-metre horse," Harrison said.

"When you see her working, she just powers to the line."

Lopartega, however, failed in her only test over further than 1600m in the Group One Australasian Oaks (2000m) in May when second last, but Harrison believes that is best forgotten.

After a strong win at Bendigo over 1600m Harrison took Lopartega to the Oaks but said by the time she arrived in South Australia she had lightened off considerably.

"She ran accordingly," he said.

"She raced up there but just weakened out of it."

Harrison has no set plans for Lopartega this campaign but hopes later in the season she can contest some black-type races for mares.

"I think there could be a good race in her along the way," he said.

After running on for fifth in a benchmark-70 over 1200m at Pakenham first-up this campaign, Lopartega scored a narrow win at the same track over 1400m.

Harrison said he was happy with how Lopartega ran on at Moonee Valley behind Hell Or Highwater and and liked how she rallied and wouldn't let third-placed Miles Of Krishan past her in the straight.

Hell Or Highwater, Tavi Bay and Firebird Flyer are at $5 ahead of Lopartega and Domino Vitale at $6.

"It's an even field again with a few chances," Harrison said.

"But I think she will be thereabouts."