PHILADELPHIA — Defense may win ball games, but when the two toughest defenses in the Ivy League faced each other Saturday, the Bulldogs found they needed some semblance of an offense too.

The Yale offense was unable to score any points for the second consecutive game, and kicker Tom Mante ’10 missed three field goals, as the Bulldogs (3–3, 1–2 Ivy) wasted another strong defensive effort in their 9–0 loss at Penn (4–2, 3–0) on Saturday.

It was the first time the Bulldogs have been shutout since last year’s 1 — 0 loss against Harvard in The Game.

Like Yale’s 9 – 7 loss to the Quakers last year, Saturday’s contest shaped up to be an ugly defensive struggle. Both offenses were kept out of the end zone, and the game’s lone touchdown came on an interception return.

“We played with great intensity, we played with great violence, we played with great effort, but those things are not enough,” head coach Tom Williams said. “You’ve got to execute, and we didn’t do enough of that today.”

At first, though, both offenses looked to be on point.

The Bulldogs’ first drive of the game lasted 13 plays for 48 yards and was highlighted by a 20-yard run by quarterback Brook Hart ’11 that brought the Elis across midfield. They did not get much further than that, though, and a 54-yard field goal try by Mante had the distance, but went wide right. With a successful kick, Mante would have tied his personal and the Ivy League record.

Capitalizing on the good field position after the miss, the Quakers moved the ball 30 yards downfield and made a 35-yard field goal to take an early 3 — 0 lead.

On the next Yale drive, a sack and a false-start penalty pushed the Bulldogs back to their own 15-yard line. Then came the huge blow. Hart’s pass on third-and-23 was intercepted and returned for a touchdown by sophomore defensive tackle Jared Sholly with 2:25 left in the first quarter.

“[Hart] basically threw it right to me,” Sholly said.

A botched snap on the point after touchdown kept the score at 9 — 0, and that’s how it would eventually end.

For the rest of the half, Yale’s offensive production was entirely absent, combining for zero first-downs and a total of 11 yards.

The Quakers too were prevented from crossing midfield until their last drive of the half. After a 15-yard face mask penalty against Yale and a nine-yard completion, Penn had the ball on the Yale 23-yard line, but the clock expired before the Quakers could spike the ball and go for a field goal.

Penn was in control throughout the third quarter, and it seemed only a matter of time before the Quakers put the game out of reach. The Bulldog defense, however, was able to force key turnovers that prevented any more points from being scored.

The first turnover came with eight minutes left in the third quarter, when linebacker Max Newton ’10 intercepted a Quaker pass at the Yale 10-yard line.

On Penn’s next drive, the Quakers once again were close to entering the red zone, but linebacker Tim Handlon ’10 forced a fumble, which defensive tackle Tom McCarthy ’10 recovered on the Yale 25-yard line.

“When we went down 9–0, we knew that we were going to have to step up and not let them score for the rest of the game,” Handlon said. “They were moving [the ball], but we were bending and not breaking.”

But Hart was unable to take advantage of the Penn turnovers, as he finished the game eight-for-13 for 56 yards with two interceptions.

The constant Quaker pressure on Hart did not help — the southpaw was sacked four times.

“[Yale’s] got tall kids who … made some nice catches,” Penn head coach Al Bagnoli said. “So [unlike last year] we were certainly much more worried about trying to get pressure on the quarterback, as opposed to just playing run defense the whole time.”

With Hart not playing well and the Bulldogs having good field position after linebacker Jordan Haynes ’12 blocked a Penn punt, Williams decided to go with backup quarterback Patrick Witt ’12.

Witt immediately provided the spark that the Bulldogs needed.

A 17-yard completion to wide receiver Peter Balsam ’11 and a personal foul against Penn on the play moved the Bulldogs within 12 yards of the goal line. After three consecutive incomplete passes, however, the Bulldogs looked like they would have to be content with three points.

But the points never came as Mante missed the 28-yard attempt — his second miss of the day — wide left with 10:01 remaining in the game.

Despite the rain Saturday, Mante said the weather was not to blame for the missed kicks.

“The conditions on the field had a minimal effect on my two field goal attempts during the fourth quarter,” he said. “I just missed them both wide left, plain and simple.”

After another defensive stop, Witt — who was the starter at the beginning of the season but had not appeared in Yale’s last two games — started where he left off, completing seven of his 10 passes to bring the Elis to the Penn 30-yard line. Once again Yale was stopped short of the end zone, and once again Mante’s field goal was wide left — this time from 47 yards out with 1:36 left.

“We feel like we have two quarterbacks who are capable of moving our football team, and when one is not operating the way we think he should, we have the ability to put the other one in, so that’s what we did,” Williams said. “We just didn’t make the plays in the kicking game that I thought we could have made that would have changed the complexion of the football game.”

The miss gave the ball to the Quakers, who were able to run out the clock after three plays.

Yale, which is already coping with this week’s revelations that strong safety Larry Abare ’10 — who broke his right arm last week against Lehigh — and wide receiver Gio Christodoulou ’11 — who is out for the rest of the season due to a turf toe injury suffered against Cornell — received another scare Saturday. In the fourth quarter as wide receiver and returner Chris Smith ’13 — Christodoulou’s replacement — walked off the field on crutches.

Smith was not available for comment about his condition, but if he is out for a substantial amount of time it would be a huge blow to the already struggling offense. Smith has statistically been one of the team’s top playmakers, having caught 18 passes for 233 yards and a touchdown.

Captain and linebacker Paul Rice ’10, who recently has been hampered by an injured knee and sat out portions of the game Saturday, had a season-low four tackles.

“I really thought that we were going to win,” Rice said. “It’s very disappointing.”

The Bulldogs will travel to Columbia next week as they try to find their offense, which has been absent since Hart’s 390-passing yard game in Yale’s 38–7 victory against Dartmouth two weeks ago.