With Oba Martins and Alan Smith leading the line, it surprised us all that Damien Duff would become a hat-trick hero, but he cetainly played to the gallery and showed the sort of form that won him two Premiership medals during his time at Stamford Bridge.
It was a sticky start, but Hartlepool had already warmed up with two fixtures in Scotland, so the Magpies were a little ring-rusty in the opening spells.
The Republic of Ireland international cancelled out Matty Robson's opener five minutes before the break and then added a second from debutant Danny Guthrie's pass before making it 4-1 at the death.
It was a sticky start, but Hartlepool had already warmed up with two fixtures in Scotland, so the Magpies were a little ring-rusty in the opening spells.
The Republic of Ireland international cancelled out Matty Robson's opener five minutes before the break and then added a second from debutant Danny Guthrie's pass before making it 4-1 at the death.
In the meantime, Guthrie had marked his arrival on Tyneside with a deflected 53rd-minute strike.
Keegan was without the injured Michael Owen, Mark Viduka, Habib Beye and Steve Harper, and his side endured a testing start.
James Milner started in central midfield with Duff playing on the right, a position which could yet be filled by summer signing Jonas Gutierrez when the season gets under way.
But the signing seems to have put an extra spring in Duff's step, and it will be interesting to see what happens when United play PSV Eindhoven when Gutierrez makes his debut. Perhaps KK will give them 45 minutes each.
James Milner started in central midfield with Duff playing on the right, a position which could yet be filled by summer signing Jonas Gutierrez when the season gets under way.
But the signing seems to have put an extra spring in Duff's step, and it will be interesting to see what happens when United play PSV Eindhoven when Gutierrez makes his debut. Perhaps KK will give them 45 minutes each.
The home side took the lead with 16 minutes gone when midfielder Robson ran on to Joel Porter's ball down the left and chipped a shot past Shay Given at his near post.
Newcastle were laboured in their efforts to get back into the game, but they were level five minutes from the break when Duff collected Milner's pass and cut inside before curling a left-foot shot past keeper Arran Lee-Barratt.
Ben Clark had to clear Obafemi Martins' scuffed effort off the line seconds later, and it took a fine save from Lee-Barratt to keep out Charles N'Zogbia's 44th-minute shot as it skidded off the rain-soaked turf with the Magpies warming to their task.
Guthrie arrived as a half-time replacement for Jose Enrique, while Shola Ameobi came on for Martins, and the former Liverpool midfielder made a swift impact when he picked out Duff, who held off Clark to slot past Lee-Barratt with 52 minutes gone.
Guthrie helped himself to the third goal within seconds when his long-range shot was deflected past the keeper.
Ameobi miskicked in front of an open goal with 56 minutes gone as the visitors threatened to run riot, but after landing an 80th-minute cross on the bar, Duff completed his hat-trick with another deft finish two minutes from time.
HARTLEPOOL: Lee-Barrett, McCunnie (Foley 55), Humphreys, Sweeney, Clark, Collins (Nelson 68), Liddle (Power 82), Jones (Boland 55), Brown (Mackay 85), Porter (Barker 76), Robson (Monkhouse 76).
NEWCASTLE UNITED: Given (Forster 65), Edgar (Tozer 62), Enrique (Guthrie 46), Cacapa (Morris 71), Taylor, Duff, Milner, Butt, N'Zogbia, Martins (Ameobi 46), Smith.
Attendance: 4,249