Barack Obama predicts Hillary Clinton victory in Pennsylvania primary

SCRANTON, Pa. — Barack Obama predicted Monday that Democratic presidential rival Hillary Rodham Clinton would get the critical victory she needs in Tuesday’s Pennsylvania primary, but said his goal is to keep it close.

‘‘I’m not predicting a win,’’ he told Pittsburgh radio station KDKA. ‘‘I’m predicting it’s going to be close and that we are going to do a lot better than people expect.’’

Clinton aides tried to downplay expectations, insisting they would be grateful for a single-digit win. While Clinton began the race with a hefty 20-point lead in several polls in the state, Obama’s extensive campaigning and heavy ad buy have significantly cut into her lead.

She told supporters in Scranton, ‘‘We really need to bear down in these last few days. The whole world is watching.’’

Pennsylvania is the largest of the 10 contests remaining, with about 4 million registered Democrats and 158 delegates up for grabs in the primary.

A Quinnipiac University poll finds Clinton at 51 percent compared to Obama’s 44 percent on the eve of the Keystone State’s primary. Clinton’s lead is slightly larger in a Suffolk University poll, 52 percent to 42 percent.

The race has remained virtually unchanged in the Quinnipiac poll since April 8, when a surge by Obama stopped. The poll also indicated Clinton has an advantage with women and voters 45 and older, while Obama performed better among men and younger voters.

Twenty percent of respondents in the Suffolk University survey said they would vote for John McCain, the Republican nominee-in-waiting, if their choice fails to win the Democratic nomination.

The poll by Boston-based Suffolk University had a margin of sampling error of plus or minus 4 percentage points. The Quinnipiac University’s poll had a margin of sampling error of plus or minus 3.1 percentage points.