The Marlboro Cup may be only the second-most interesting race on the program at Belmont Park today. After all, big-money championship confrontations happen a few times a year. But how often do sure-fire, mortal-lock betting opportunities come along?

It is rare to find a horse with credentials as overpowering (and yet somewhat subtle) as those of Solo Native, who figures to win the ninth race at Belmont in a runaway.

Solo Native raced in England with limited success last year, then went to California and ran twice on the turf this summer at Del Mar. He lost an allowance race by a nose in his last start, and today runs in a one-mile allowance race under similar conditions.

New York bettors, who generally aren't familiar with California form, have no way of knowing what a powerful pair of races Solo Native has run in this country. He finished fourth in his U.S. debut, a minor stake, but our Del Mar sources tell us, "He had to take up sharply and was absolutely wiped out. He should have won by a mile."

Then, when he was favored in an allowance race, Solo Native was parked at least three wide all the way around the track, and was only caught in the final stride by a rival who had sneaked through along the rail. The time of the race, 1:48 3/5 for 1 1/8 miles, was excellent. But the real evidence of Solo Native's merit came from the subsequent performances of the horses he beat in that allowance event.

Creeksarosa, who finished third, came back in an allowance race against a favored rival who had just lost a stakes race by one length. Creeksarosa won decisively.

Emperdori, who finished fourth behind Solo Native, won his next start against a good allowance field.

Catane, who finished fifth behind Solo Native, was entered in an impossible spot the next time he ran -- the $125,000 Del Mar Derby. Sent to the post at 124 to 1, he rallied to finish third, beaten by only two lengths.

All this evidence suggests that Solo Native has at least enough ability to be competitive in low-grade stakes races. He may be much better than that. His 11 foes at Belmont have no such pretensions. Most of them are claimers, or else horses who have tried and failed repeatedly against similar allowance company.

The only ones in the field who may have some quality are Lieutenant's Lark, who won his first race on the grass by six lengths in his last start, and Dual Honor, a Seattle Slew colt who is making his first start on the turf. But Solo Native has the established grass-running ability and the established class. Moreover, he has a top California trainer, John Gosden, and a great jockey, Laffit Pincay Jr.

It is hard to guess what price Solo Native will be. If the race were being run in California, he would properly be an odds-on favorite, but a New York crowd unacquainted with his virtues may let him get away at 2 to 1.

For bettors who want more of a return, the ninth race is the second half of Belmont's late daily double, the first half of which is the Marlboro Cup. It easily could be an all-California, all-Pincay combination of Greinton and Solo Native.