Wes Hoolahan's late winner ensured Blackpool go into the second leg of their Coca-Cola League One play-off semi-final against Oldham as clear favourites.
The Blackpool midfielder skipped around substitute Oldham goalkeeper Alan Blayney in the 87th minute and slid the ball into an empty net to give Simon Grayson's side a priceless lead.
Shaun Barker had headed the Seasiders, who have now won their last eight matches, into an early second-half lead, but veteran Oldham winger Andy Liddell fired John Sheridan's side back into the tie by holding his nerve to convert a controversial 75th-minute penalty.
Blackpool should have carved out an even bigger lead, with Keigan Parker missing a hat-trick of clear-cut chances.
The opening period, played out in torrential rain and at helter-skelter pace, was an even affair in front of a near full house at Boundary Park.
But Blackpool, appearing in their fifth play-off, seized control at the start of the first period and showed why they have lost only six League One matches since the end of September.
Oldham fielded the same side that lined up for their last-day win over Chesterfield, while Blackpool made just one change from the side that thrashed Swansea 6-3 in their final League One match, with Paul Rachubka taking over in goal from Joe Hart.
Oldham created the first opening, but leading goalscorer Chris Porter headed Liddell's corner tamely into Rachubka's hands before the home side were given an early scare.
Parker skipped round Sean Gregan following Andy Morrell's flick, but shot straight at big Australian keeper Les Pogliacomi when he appeared set to score and then fired the rebound over the crossbar.
Gregan was found wanting by Parker again soon after and booked for dissent following a clumsy challenge and Richard Wellens was also shown the yellow card against his former club for a scything tackle on Hoolahan.
The football was fast and furious in the torrential rain. Claus Jorgensen was next to be cautioned by referee Iain Williamson for seeking retribution on Wellens and Oldham striker Paul Warne was temporarily forced off the field after being caught by Keith Southern's errant arm.
Blackpool left-back Robbie Williams rifled a 25-yard shot over the crossbar, but chances were few and far between.
Blackpool full-back Terrell Forbes was the fourth player to go in referee Williamson's notebook just before half-time for his challenge on Chris Taylor.
Blackpool pushed Oldham onto the back foot at the start of the second half and Parker spurned another gilt-edged chance to fire the Seasiders into the lead.
Forbes burst into the penalty area but when the ball fell to Parker the number seven dallied and his shot was smothered by Pogliacomi.
Moments later the Latics keeper was picking the ball out of his net.
Williams fired over a perfect corner and Barker rose above the home defence to power home a header into the top corner to send almost 4,000 travelling fans behind the goal wild.
Barker almost repeated the feat soon after as Blackpool looked to take the tie by the scruff of the neck.
Pogliacomi was forced off with what appeared to be a pulled muscle and replaced by Blayney, while the Latics sent on Paul Edwards for Simon Charlton.
Blayney pulled off a fine save to deny Parker in another one-on-one and followed up with a stop from the same player's shot soon after.
Parker, by now causing Oldham all kinds of problems, sent Morrell clear, but Blackpool's leading goalscorer overran the ball.
Oldham were given a controversial lifeline out of the blue in the 75th minute when a rare attack saw Porter go to ground under a challenge from Blackpool skipper Michael Jackson.
Referee Williamson immediately pointed to the spot and Liddell buried his penalty into Rachubka's right-hand bottom corner.
But just when it appeared Oldham would go to Bloomfield Road all square, Morrell played in Hoolahan with a superb pass and the midfielder finished with aplomb to give Blackpool the lead they deserved.