NEW YORK--The Harvard football team, down 17 points early in the second half, bounced back to steamroll Columbia, 49-17, here this afternoon in front of 7921 at Lawrence A. Wien Stadium at Baker Field.

The same Crimson offense that gained 54 total yards in the first half--and just eight on the ground--ripped apart the Lion defense after a field goal gave the hosts a 17-0 advantage at 6:43 of the third quarter.

Lamont Greer, Brian White, Rufus Jones, Robert Santiago, Santiago again and Brian O'Neil scored touchdowns in just over 15 minutes in the third and fourth quarters to spoil the debut of Columbia Coach Jim Garrett and to give Harvard its biggest point total since it spanked the Lions, 57-0, in 1973.

The loss extended Columbia's non-winning streak to 15.

Garrett, who has promised to reverse the dismal football tradition in Gotham, brought his troops out on a wave of enthusiasm in the first half.

Columbia took over on the Harvard 41 after a short Rob Steinberg punt, and the Lion linemen took over.

Chirico went up the middle on a well-exucuted trap for a quick 22-yard gain. Two plays later, Santos scrambled from the 14 to within inches of the Harvard goal line, and Chirico took it in from there. The extra point put the hosts on top, 7-0.

After the kickoff, three Harvard plays and a 44-yard Steinberg punt, the Lions took control again, this time at their own 23.

Santos picked the Crimson defense apart, connecting on six strikes for 83 yards and a touchdown.

The senior quarterback from Edison, N.J., struck Homer Hill all alone in the middle of the end zone at 11:58 for the second Lion score to top the hosts' impressive eight-play, 76-yard drive.

The Crimson mounted its first serious threat of the afternoon, but a White fumble in the Harvard backfield stymied the drive at the Columbia 29-yd. line.

The two teams exchanged turnovers as the Lions' momentum slowed and the Crimson offense began to adjust to the new Columbia defense introduced by Garrett.

The Crimson miscue was particularly costly as White floated a pass intended for split end Joe Connolly into the arms of Lion defensive back Ron Hartz.

But time and the blistering heat took their toll on the Lions, who wilted in the last 25 minutes.

The first half was a statistical nightmare for the Crimson. Columbia engineered four times as much total offense as Harvard, including 103 yards rushing to Harvard's eight.