Occasionally, luck is the most important factor in attempting to cover the NFL spread. Two selections made this season illustrate the point.

Last Sunday, at Houston, the Oilers were favored by nine over Tampa Bay and were in control, 20-7, in the fourth quarter. They were headed for another touchdown or field goal when Earl Campbell took a handoff from Kenny Stabler.

Campbell thundered for a career-high 203 yards, on 33 carries, for the day. This time, however, he fumbled. Tampa Bay recovered and returned the loose ball 80 yards for a touchdown. Houston, instead of winning by 13, 16 or 20 and beating the spread, won, 20-14.

A Monday morning look at the statistics showed that Houston had 23 first downs to 12 for Tampa Bay. The Oilers rushed for 245 yards and passed for 222, compared with the Bucs' 78 and 126. This dominance, by any standard, is the sort of statistical superiority that should make covering nine points fairly easy.

But luck turned a winning kick into a losing proposition.

Too many bettors, unfortunately, tend to acknowledge luck's role only when they lose. I should, for instance, be equally quick to mention a winning selection of Sept. 21 at Houston as an example of exceptionally good fortune. s

On that occasion, the Oilers, a seven-point favorite over Baltimore, were leading, 21-9, late in the final period and were headed for another score deep in Colt territory. The situation was quite similar to that of last Sunday. Against Baltimore, the Houston drive ended when a player foolishly tried a lateral that was intercepted by a Colt player. A few minutes later, with less than two minutes remaining, Baltimore scored and covered, 21-16.

So it works both ways, good luck and bad. All the handicapper wants, or has any right to expect over the long haul, is for half of the crazy bounces to go his way. Just give him 50 percent, and the magic figure of 52.37 that separates winners from losers -- providing each bet is made in the same amount -- should be attainable.

It is always possible, in any one season, that a bettor will enjoy a prolonged run of good or bad luck. But over a number of years, this will even out. Any person who doesn't believe that, who swears that he has been unlucky three or four years in a row, is only kidding himself. He should look for another reason behind the lack of success.

After 30 kicks this season, my record stands at 15-15 and a net loss (basically the vigorish) of $350. Fear not. Prime time play is just beginning. The betting year is 20 weeks long. There is only one figure that counts: the one after Super Bowl Sunday.

I salute the New England Patriots for their performance last week in Baltimore, even though it cost me a highly profitable afternoon, what with Philadelphia having covered against Dallas. The Patriot offense was mistake-free, imaginative and beautifully directed by Steve Grogan. There's not a better team in the league right now.

I still like Baltimore, too. So, Sunday, there's an opportunity to back both squads -- an imaginary $250 on New England favored by two at Buffalo and $250 on the Colts at home, favored by seven against St. Louis' patched-up offensive line. Washington's on the way back and worth $250 as host to winless New Orleans, giving 10. The Redskin offensive front is back in working order, after three injuries.

Kansas City's young, improved squad attracts $250, as a three-point favorite over Detroit. The Chiefs, winner of three straight, are at home. I'll also send in an imaginary $250 on Houston giving six in the Astrodome to Cincinnati. Dave Casper gives Stabler another exceptional attack piece.

The week's two $500 picks are Dallas and Los Angeles. Dan Fouts' usually impenetrable Charger pass protection will be hard-pressed to hold out Randy White and friends. This is a classic matchup, where the edge goes to the home team, favored by two. The Rams, on the other hand, have the NFC's best offense. Atlanta will need a lot of luck to produce an upset. L.A. is favored by four.

In other games, Las Vegas lists Philadelphia 7 1/2 over Chicago, Denver six at the New York Giants, Green Bay one over Minnesota, Pittsburgh six at Cleveland, Oakland three over Seattle, Tampa Bay two at San Francisco and (Monday night) the New York Jets one over Miami.