The son of Mastercraftsman looked a force when scooting to a five-length success in the racingtv.com Handicap over a mile and three-quarters, and appears to be quickly rising up the ranks.
Though a general 33/1 chance for the final British Classic of the season on September 10, Botti will adhere to the wishes of the colt's owners, Scuderia La Tesa Limited, and send Giavellotto to Doncaster.
"The St Leger is still very much on the cards," said trainer Marco Botti. "I know people will say it is a big shot, and maybe it could be a step too high, but we ran at Newmarket because we wanted to give him a bit more time.
"The perfect race would have been the Melrose Handicap (at York on August 20), but it is only a couple of weeks away and it would be just 20 days to the St Leger, so we thought we would give him a little bit more time if we aim at the St Leger.
"I think the timing is perfect. He has shown he stays well and he has improved."
Giavellotto has had five runs this term, winning twice and being placed in two other valuable handicaps.
The one blip on his upward curve came at Sandown in April, when he finished four and three-quarters lengths behind Red Vineyard over an inadequate 10 furlongs.
Botti added: "We always thought he was going to be a nice horse earlier in the season, but we were a bit disappointed when he only finished fourth at Sandown.
"But looking back now, he wasn't a mile-and-a-quarter horse. Obviously he is a proper stayer.
"He is a big horse and is just filling his frame. He has just come to himself. He handles good to soft ground and fast ground, and the owners were keen to take a shot. They said they would rather go to the St Leger than another handicap.
"The Melrose is a valuable handicap, but we all know it is a big field and he will go up (in the weights) again, and he is carrying a lot of weight anyway. The St Leger is worth a shot."