CAMBRIDGE, Mass. – An inability to stop Harvard's inside game has ended Penn's unbeaten mark in the Ivy League and forced a tie at the top.

With 6-foot-9 Chris Lewis and 6-7 Seth Towns continually converting close to the basket, Harvard defeated Penn, 76-67, on Saturday afternoon at Lavietes Pavilion.

The loss snapped a five-game win streak for Penn, now 17-7 overall and 7-1 in the Ivy League. Harvard improved to 12-11, 7-1.

Penn trailed by seven points at the half and never got any closer over the final 20 minutes.

Lewis, whose previous career high was 22 points, scored 25, while Towns added 17. Ryan Betley led four double-figure Penn scorers with 16 points while AJ Brodeur added 14 points and seven rebounds.

"Chris Lewis is a much improved player, finishing with his left," said Penn forward Max Rothschild, who had 12 points in 19 minutes. "He is a big man. Credit to him and how he has improved."

Lewis scored most of his points down in the blocks.

"This is really big for us, a great confidence booster," Lewis said.

It also showed Penn where it needs work, especially in post defense.

"I thought Lewis played great," said Penn coach Steve Donahue, whose team committed 11 turnovers, compared with six for Harvard. "That hasn't happened to us. We had a little injury bug going on inside, Max wasn't 100 percent but that said, they got confident and did a great job."

Penn, which trailed by as many as 16 points midway through the second half, cut the deficit to 70-63 when guard Darnell Foreman scored on a turnaround jumper with 2 minutes, 32 seconds left.

Towns came right back to hit a three and Penn missed two three-pointers on its next two possessions to erase any doubt. The win was even more impressive since Harvard played without second-leading scorer Bryce Aiken (14.1 ppg.), who was out with a knee injury.

It wasn't an easy weekend for Penn,which escaped with a  64-61 win Friday at last-place Dartmouth.

With six Ivy League games left, it appears that Penn and Harvard will battle it out for the regular-season title. Every other Ivy League team has four or more league losses. Harvard will visit the Palestra on Feb. 24.

"Our goal wasn't to try to go undefeated, [but] we try to win every game, obviously," Rothschild said. "It is nice to have a little bit of a wake-up call."