Louisiana State, with a 17-3 opening victory at Texas A&M, advanced four places to No. 6 in the first regular season ratings in United Press International's coaches' poll.

Oklahoma maintained its hold on No. 1 with 44 of 50 first-place votes. Nebraska stayed at No. 2 and had one first-place vote. No. 3 UCLA and No. 4 Auburn each advanced a spot while No 5 Ohio State fell two positions.

Following LSU was No. 7 Miami, No. 8 Michigan, No. 9 Penn State and No. 10 Clemson. Rounding out the top 20 were No. 11 Florida State, No. 12 Arkansas, No. 13 Washington, No. 14 Arizona State, No. 15 Tennessee, No. 16 Notre Dame, No. 17 Alabama, No. 18 Pittsburgh, No. 19 North Carolina and No. 20 Southern Cal.

The final three teams were new to the top 20. Texas A&M, Iowa and Florida dropped out.Complete UPI listing, Page F7

Brian Davis, Parade Magazine's 1984 national high school football player of the year, has enrolled at Montgomery-Rockville, but has been ruled ineligible this season.

The former Washington (Pa.) High School scholastic all-America running back originally enrolled at Pittsburgh, making his debut by rushing for 100 yards in the second half of Pitt's 29-22 loss to Boston College in 1985. He was suspended for one year in January because of academic troubles.

Montgomery Coach Phil Martin said Davis needed 24 credit hours with a 1.75 grade point average in order to be eligible this season, but could transfer only 16 hours from Pitt.

Davis has told Pitt officials he would like to return in 1988.