Just past the half hour and Crewe were 2-0 up after strikes by Seth Johnson, a shot deflected off Andy Todd, and Rodney Jack, who collected Shaun Smith's clearance and charged 50 yards before curling a right-foot shot across Jussi Jaaskelainen. Previously Bolton had been lethargic, now they were stunned too.
"If you let your standards slip you run the risk of falling flat on your face," Colin Todd, Wanderers' manager, said. "That's what happened to us here and we have no excuses. We didn't get going and didn't perform in any area."
He shuffled his pack at half-time but the second period was barely a minute old when Colin Little's pass set Jack free again and he tucked away the chance with relish.
"Even when we aren't playing well we should be good enough to keep clean sheets," Todd added. "Our lack of discipline was poor."
Dean Holdsworth pulled one back with a 55th-minute penalty but Bolton's 15-match unbeaten record ended and they dropped to fourth. It was no way to celebrate their 2,000th home game.
The two clubs - Bradford City and Ipswich Town - also chasing the second automatic promotion place behind Sunderland continued their neck-and-neck race with 1-0 wins at home to West Bromwich Albion and at second bottom Bristol City respectively.
Bradford, who had won just once and drawn three in their five previous matches, scored in the third minute when Wayne Jacobs' shot took a cruel deflection off Paul Holmes. "It wasn't a fluent performance," Paul Jewell, the Bradford manager thought. "We had enough chances to have won two games and had it gone to 2-0, I am sure we would have gone away with the game. But at 1-0 you are always hanging on."
Ipswich's winner at Ashton Gate was scored by Richard Naylor, his fourth of the season. But it was the East Anglian side's England Under-21 goalkeeper, Richard Wright, who kept the points secure.
One place above Bristol, Bury remain in peril thanks to wretched away form which has seen them go all season without a League away win and only six draws in 17 matches, following the 4-0 defeat at Tranmere Rovers. "It's no good kidding ourselves. It was embarrassing," Neil Warnock, the Shakers manager, admitted. "The game should have been dead after 20 minutes. Tranmere won every tackle, header and second ball."
Port Vale's revival under Brian Horton stalled at Fratton Park where Portsmouth made it eight games unbeaten by thrashing them 4-0.
For Vale, who had Neil Aspin sent off, it was a 10th successive away defeat, a reverse engineered by the striker Guy Whittingham, on loan from Sheffield Wednesday, who scored a hat-trick.Reuse content