Both teams were in midseason form in their opening game today as the Philadelphia Eagles completely outclassed the hapless New York Giants for the 12th straight time.

The Eagles opened defense of their National Conference championship by defeating the Giants, 24-10, before an unhappy crowd of 72,459 on a mild, cloudy day at Giants Stadium.

Although there is little optimism surrounding this 18th year of the Giants' rebuilding program -- they haven't made the playoffs since 1963 -- their fans didn't start booing until the second quarter after the home team had botched two excellent scoring chances, fumbled away another opportunity and allowed an 81-yard scoring drive.

By the time the bumbling Giants finally put together a scoring drive late in the fourth quarter, the stadium was more than half empty. The Giants, who face the Redskins in RFK Stadium next Sunday, may have trouble matching last season's 4-12 record.

The Eagles, meanwhile, displayed a pass rush that may be the equal of the Dallas front four of Too Tall Jones, John Dutton, Randy White and Harvey Martin.

On passing situtations, Coach Dick Vermeil scraps his usual 3-4 alignment, inserts Ken Clarke and rookie Greg Brown up front, moves Claude Humphrey from end to tackle and leaves Carl Hairston at right end.

Poor Phil Simms. After the Giants fell behind 17-3 midway through the third quarter, the young quarterback was forced to play catch-up and the eager Eagles teed off. They were credited with six sacks for 66 yards and forced Simms into throwing many ineffective passes.

"I was very pleased with our defense, particularly our pass rush," Vermeil said. "We kept enough pressure on them that they couldn't get too wide open against us."

Although Simms managed to complete 20 of 37, only five were caught by wide receivers. Most were simply safety valve tosses to his running backs for little yardage.

"I thought we established pressure early and kept it up until that last drive," said veteran linebacker Frank McMaster. "They ran a lot of screens and short stuff, but they didn't get a chance to go deep. I thought it was very important that we stopped them early when they could have scored twice. You never want to let a home team get in front early and get the crowd behind them."

The Giants had an opportunity to score on their first possession after Alvin Garrett returned a punt 18 yards to midfield. An 11-yard pass on first down and five running plays brought the ball to the 23, but tight end Tom Mullady dropped a pass over the middle on third down. Joe Danelo then missed a 40-yard field goal attempt.

Minutes later, the Giants were on the move again. Passes to running backs Bo Matthews, Billy Taylor and Leon Perry brought the ball to the 22. The drive reached the five before the Eagles stiffened and forced the Giants to settle for a field goal.

"If they had scored a couple of early touchdowns, it could have changed our game plan," Eagle quarterback Ron Jaworski admitted. "But our defense did the job all last season, and they didn't put us in a hole today."

Jaworski's pattern was similar to Simms' although for a different reason. He enjoyed almost perfect protection, but the Giants took away his deep patterns by double-covering the wide receivers.

"For the most part, their defense dictated what we were going to do," Jaworski explained. "They blitzed a lot with their linebackers and when I saw them coming, I just dumped the ball off to my backs."

The Eagles' three top receivers were running backs. Wilbert Montgomery caught six for 33 yards, Perry Harrington grabbed four and Billy Campfield had two for 31 yards.

Jaworski's one truly long pass turned into the game's most exciting play, a 55-yard pass-and-run touchdown to Rodney Parker midway through the third quarter that put the Eagles in command, 17-3.

"They were playing bump-and-run and that's not a high-percentage pass," Jaworski said. "But if you hit it, it's going for the distance. Rodney made a great catch because he was well-covered."

Parker, a second-year man who caught just nine passes last season, outleaped veteran safety Beasley Reece around the 20 and raced down the sidelines untouched.

The Eagles wrapped it up two possessions later when they drove 64 yards in eight plays, plus three personal foul penalties. After rookie Hubert Oliver failed twice from the one, Montgomery swept right end for the touchdown.

With Harrington and Oliver filling in for the injured Leroy Harris, the Eagles outgained the Giants 178-55 on the ground and gave every indication that their rushing game will be just as potent as last season's.

Vermeil probably summed up the methodical victory best when he said, "We have better football players than the Giants and we should beat them."