The golf team suffered a shattering 4-3 upset loss to Holy Cross yesterday to end a four-match winning streak and cast serious doubt on the squad's ability to stand up to Ivy powers Penn and Columbia today in New York.

The match, on the long Pleasant Valley course in Sutton, teeter-tottered most of the afternoon. The individual contests were all runaways, but they were evenly balanced, three and three, until the last in which Carl Cunney of the Crusaders knocked off Roger Wales of Harvard on the final hole, one up.

The defeat dropped the Crimson's overall mark to 4-2. Holy Cross, which was not expected to be much competition for the improving Harvards, gained its first victory of the year against two losses.

Bruce LoPucki, at number one, was dealt the most shocking setback, a four and two loss to Mike Corbett. LoPucki, a former USGA Junior semifinalist, had been shooting in the middle 70's most of the season and had only dropped one other match - to Navy, one of the bast in the East.

The victories alternated all the way down the line. Bo Keefe, playing number two whipped his opponent handily, 5 and 4. Paul Oldfield, a sophomore like LoPucki, lost the third match, 4 and 3.

Brian McGuinn, the captain and one of the few men on the team to get in some practice over the past week, clobbered his opponent, 7 and 6. McGuinn is steadily improving and may soon regain the number one spot he held last year and the year before.

Tow Wynne, the third sophomore on the team, lost a fairly close match on the sixteenth hole. 3 and 2. And veteran Bob Sinclair won again in sixth position. 5 and 4.

The loss to the Crusaders, close after important wins over Williams and Boston College, could demoralize the inexperienced squad. The team had four newcomers in the top five positions, and all three of the sophomores who saw extensive action last year - won their matches.

McGuinn says that the squad is keying on the Greater Boston Collegiates next week and the Yale match here in a month. Yesterday's loss could be a severe blow.