The Andrew Forsman-trained Mustang Valley was on a plane back to New Zealand on Sunday after an excellent run for fifth in the Gr.1 Doncaster Mile (1600m) at Randwick.

The four-year-old daughter of Vanbrugh was shuffled back to last on the fence rounding the home bend, but charged home once a run appeared and was a little unlucky not to fill a minor placing behind fellow Kiwi-bred Mr Brightside.

"It was a very good run. It is hard to get back in such a big field of good horses and give them such a start," Forsman said.

"To make up the ground and to be beaten less than two lengths, it was clearly a very good run. She just needed a bit more room at a more advantageous time."

Already a Group One winner, Mustang Valley will have a strong chance of doubling her elite-level tally when she contests the Gr.1 NZ Thoroughbred Breeder's Stakes (1600m) at Pukekohe on Saturday.

"At this stage we will head there, provided she travels home okay and does well in the next few days, but I am sure she will," Forsman said.

"We could have hung around here (in Sydney) and hoped that the rain kept up, but I think she is a stronger winning chance back at home."

The Cambridge trainer was left lamenting what could have been in the Gr.1 Australian Derby (2400m) with his charge Full Of Sincerity, who got into an awkward position in the stop-start race and finished

"It was pretty frustrating, to be honest. When horses made the move down the back straight, he just got caught in a pocket and was really in tight quarters for a fair way," Forsman said.

"He got a bit of buffeting and by the time he got out and was able to have a crack at them, it was all over."

Whether Full Of Sincerity returns to New Zealand is still to be decided, with plenty of Australian options for the OTI-raced son of Puccini.

"That is something we will discuss in the next day or so. Obviously, we have got options for him. He is placed in a (New Zealand) Derby and I think he would be quite easily placed in the Spring."

Forsman, who will open a base at Macedon Lodge in Victoria later this month, hasn't ruled-out continuing on with the campaign with the young stayer.

"Potentially. I wouldn't necessarily rule that out. We will give him a quiet day or two and just see where we get to," he said.

While Mustang Valley  has jetted home, Forsman has called for reinforcements, with smart two-year-old filly Ethereal Star arriving in Sydney for a tilt at the A$1million Gr.2 Percy Sykes Stakes (1200m) at Randwick next weekend.

Winner of the Listed Challenge Stakes (1100m) and runner-up in the Karaka Million 2YO (1200m), the well-bred daughter of Snitzel trialled well last week at Taupo sporting blinkers.

The filly has previously won on a Heavy track, but Forsman was still unsure as to whether Ethereal Star would handle a rain-affected Randwick track should Sydney's wet weather persist.

"You strike different types of rain-affected tracks. She got through it okay when she won the stakes race at Pukekohe. But what it was like that day to what it was like here (in Sydney) is very hard to compare," Forsman said.

"We have toyed around with the blinkers a little bit. I had a good talk to Damian Lane about it. He will ride her on Saturday. I think for now we will probably elect to leave them off. It probably works for and against her in a lot of ways.

"We are going back to what worked for her in the past and hopefully that does the trick."

Meanwhile, Forsman was pleased with the effort of smart two-year-old filly Aprilia, who finished second in the Gr.1 Manawatu Sires' Produce Stakes (1400m) behind Pignan on Saturday. 

"I was really happy with her. It was a shame not to get the win. Trobriand didn't quite give her the cart into the straight that we had hoped. He dropped off quite quickly and then Pignan got the good run up the inside," he said.

"She got left a bit flat-footed at that stage and then came again when it was all over, but it was a very brave run.

"We will see how she pulls up. There is not heaps for her left in New Zealand but if she is going to be a spring contender she is going to have to get to the paddock at some point."