Championship games involving the Baggies this season have produced more goals than any other team and there were another five at The Hawthorns, with all of them coming in the opening 45 minutes.
In a first half littered with questionable defending, Ben Watson's first of his loan spell and Chris Brunt's 11th of the season handed Albion a two-goal lead after just nine minutes.
Birmingham-born Sean St Ledger pulled one back with a diving header before Graham Dorrans' superb 30-yard free-kick made it 3-1 just after the half-hour mark.
An exciting first half was not over there, though, as Neil Mellor again reduced the arrears but a goalless period after the break ended North End's five-match unbeaten run.
Having not even got out of first gear in the opening 10 minutes, Albion found the game theirs to lose.
They took the lead with their first meaningful attack as Robert Koren exchanged passes with Ishmael Miller and the Slovenia captain crossed from the right for the unmarked Watson to sweep home into the bottom corner.
Before North End could catch breath it was 2-0 when Dorrans was left with the freedom of the Black Country to pick out Brunt in plenty of space, and with red shirts appealing for offside, he was afforded plenty of time to do the rest.
But it was game on again with 15 minutes on the clock as St Ledger capitalised on poor Baggies defending to reduce the arrears with a well-taken diving header from Ross Wallace's cross.
Despite leading, West Brom were struggling to get going although every time they ventured forward they looked dangerous.
And they soon restored their two-goal advantage, unsurprisingly with the help of more poor play from the visiting back five.
Dorrans, last Sunday voted the second best player outside the top flight at the Football League Awards, curled a stunning 30-yard free-kick into the top corner which was only helped on its way by the flapping efforts of keeper Andy Lonergan.
But Preston again refused to give up the ghost and, with a healthy suspicion of offside, made it 3-2 at the interval as Mellor raced clear and rounded Scott Carson before firing home.
Carson did extremely well to tip former Baggies midfielder Richard Chaplow's free-kick around the post at the start of the second half as, in similar fashion to the first, Preston started the better.
Lonergan then did just as well at the other end to parry Watson's effort to safety with the game levelling out, before Gabriel Tamas saw his header cleared off the line by St Ledger.
The next goal was always going to prove crucial and Lonergan produced a smart double stop to deny Miller before Dorrans blazed over when in a great position to wrap things up.
Nerves swept around The Hawthorns during the final 15 minutes but the hosts held on to inflict an eighth successive league victory over Preston on home soil.