Norway have lost only once in their past 18 matches and will take on France in a compelling battle for top spot in the group in Boston on Saturday.
Senegal must beat Iraq, who are also without a point, in their final game to stand a chance of avoiding an early exit.
Led by the unstoppable Haaland, who increased his astonishing international goals tally to 59 in 52 games, Norway recorded back-to-back wins at the World Cup for the first time.
They added weight to the belief they can do serious damage at these finals with a dominant display against a Senegal side that paid heavily for their errors.
Norway quickly set the tone as Kristoffer Ajer’s header forced Senegal goalkeeper Edouard Mendy into a terrific save with his legs at a corner, but they lost full-back Julian Ryerson to injury early on.
Captain Martin Odegaard skied over an inviting cut-back from the right for Norway, as Nicolas Jackson looked Senegal’s most dangerous threat.
Mendy again came to Senegal’s rescue with a superb block to deny Odegaard after Haaland cushioned down Antonio Nusa’s chipped cross into the box.
But Mendy allowed Pedersen’s low drive to creep under him after a dreadful mistake from skipper Kalidou Koulibaly gave the ball to the replacement right-back on the edge of the box.
Haaland rolled against the post from a tight angle after Mendy got in a tangle, but he made amends three minutes into the second half as Norway sliced Senegal apart on the counter-attack.
Odegaard surged upfield and slid a pass through to Haaland, who buried an emphatic finish past Mendy to add to the two goals he scored in Norway’s opening 4-1 victory over Iraq.
Senegal clawed their way back as Sarr showed great composure to poke home after tumbling to the ground following a clever flick into the area by Sadio Mane.
However, Koulibaly was at fault once more, failing to clear as Haaland steered a volley in off the crossbar from Patrick Berg’s cross, delighting Norwegian fans who provided a colourful backdrop with their viral rowing chant.
Mory Diaw came on for the injured Mendy in goal, but only a headed goalline clearance from Pathe Ciss prevented Oscar Bobb from netting Norway’s fourth.
Sarr’s second of the night set up a tense finish, but Norway held on to join France in the next round and leave Senegal’s hopes hanging by a thread.
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