Lovren’s thunderous half-volley gave the Reds a 1-0 half time lead on Merseyside, before Salah’s penalty just after the break made it two.
Swiss international Shaqiri tapped home a third from Trent Alexander-Arnold’s low cross before substitute Fabinho wrapped up the scoring with a close-range header, consolidating the hosts’ place at the top of the table on a miserable afternoon for Rafa Benítez’s men.
United created the first opening of the day when Matt Ritchie’s cross cleared Virgil van Dijk and was met by Joselu, but the United forward – preferred to Salomón Rondón in attack – planted his free header into the ground and it bounced wide.
Even before Lovren’s early opener, the Magpies had already heeded one warning. Andy Robertson and Roberto Firmino combined to release Sadio Mane on the left, but his cutback was sliced past the target by Shaqiri.
But the hosts’ goal took little longer to arrive. Robertson swung a cross in from the left and when Jamaal Lascelles’ headed clearance dropped at Lovren’s feet, the Croatian pounced. His first-time strike was crisp and left Martin Dúbravka helpless as it flew into the roof of the Kop end net.
Jurgen Klopp’s men, unbeaten in the Premier League heading into the contest, continued to probe. Firmino’s cute pass almost played in Mane and van Dijk had a go before Dúbravka was forced to tip Shaqiri’s deflected free kick over the bar in the half’s dying minutes.
Barely a minute after the restart, Liverpool had the chance to make it two. Salah made his way into the box from the right and went down under pressure from Paul Dummett, and referee Graham Scott pointed to the spot. The Egyptian showed no mercy, dispatching low beyond the reach of Dúbravka to double his team’s advantage.
It was a disastrous start to the second period for Benítez’s charges, and but for Federico Fernández’s timely interception when Mane broke clear and crossed moments later, the deficit could have been greater. Lascelles’ misplaced pass led to the Senegalese winger being put through down the right but, with Salah and Firmino waiting to pounce, Fernández got his foot to the final ball and Dúbravka was able to gather.
Joselu glanced DeAndre Yedlin’s cross wide at the other end but Liverpool came looking for more, with Mane’s miscuing an overhead kick and Dúbravka getting down low to his right to prevent Firmino from converting Salah’s centre.
Sean Longstaff was sent on for his Premier League debut and played his part in helping United get forward just before Ritchie’s teasing cross was prodded wide by Isaac Hayden.
But the youngster’s cameo proved to be one of the few bright spots on a Boxing Day to forget for the Magpies. Shaqiri stabbed home Liverpool’s third with just over ten minutes left on the clock, before Fabinho completed the scoring late on, finding space in the six-yard box to meet Salah’s corner and nod past Dúbravka.
