Rep. Tom Allen (D) was trailing Sen. Susan Collins (R) by single digits in a poll paid for by the Democratic Senatorial Campaign Committee.

Collins led Allen 49 percent to 41 percent in the Mellman Group poll of 600 likely voters taken Sept. 30-Oct. 2. Undecided voters accounted for 10 percent in the poll, which had a margin of error of 4 points.

It’s the smallest lead — 8 points — that Collins has held over Allen in public polls in recent months. According to the DSCC, Collins’ lead has shrunk from 15 points over Allen since Mellman conducted a poll in June.

The poll also showed Democratic presidential nominee Sen. Barack Obama (Ill.) with a commanding lead in Maine over GOP nominee Sen. John McCain (Ariz.), 52 percent to 35 percent. Thirteen percent said they were undecided in the presidential contest.

Despite the state’s Democratic leanings, Allen has had a difficult time closing the gap between him and Collins, even after both candidates hit the television airwaves.