Twice Over won by a short-head in Thursday's Guineas trial
Twice Over beat Raven's Pass in the Craven Stakes and trainer Henry Cecil indicated he may skip the 2,000 Guineas and make the Derby his main target.
The two market leaders pulled clear of eight other rivals before fighting it out inside the final furlong.
It appeared John Gosden's charge had the advantage but Cecil's colt, who won over 10 furlongs at two, just outstayed his rival in the one-mile contest.
Twice Over then earned a quote of 4-1 with Ladbrokes for the Guineas.
The same bookmaker had him at 5-1 for the Derby, with New Approach remaining favourite for both races.
The winner was sent off as the 9-4 second-favourite in Thursday's big race at Newmarket and prevailed by a short-head, with a yawning six lengths back to The Bogberry.
Twice Over's jockey Ted Durcan said: "It was a strong-run race the whole way and they didn't mess around at all, we went nice and strong the whole way.
"He was lovely and settled, he's an easy horse to ride - if anything he idled slightly.
We are not certain he is a Guineas horse and I don't want to push him if it is not the right race for him
"He's a horse that hasn't had many runs so having a race today and getting a smack will really help him.
"He stayed extremely well, but he settled also so when the other horse came I knew that when I gave him a smack he would pick up again.
"He'd been working really well at home, but Mr Cecil also left loads of room for him to improve. Hopefully he'll be a smashing horse."
Cecil added: "He was ready for a race, but obviously he will improve a lot.
"We are not certain he is a Guineas horse, though, and I don't want to push him if it is not the right race for him. We'll see.
"We need to see how he progresses. He did everything right as he has only had nice work and he was ready for a race.
"Whether he outstayed the other horse I'm not sure but it was certainly a nice performance because he is only a baby really."
Craven Stakes (Newmarket)
1. Twice Over (T E Durcan, 9-4 )
2. Raven's Pass (J Fortune, 11-8 fav)
3. The Bogberry (J Murtagh, 28-1 )
Distances: Short Head; 6 lengths; 1½ lengths