The hosts were thrashed 4-0 by Paris Saint-Germain last Friday as their abysmal run continued, while Lens suffered an unexpected defeat to Nice in their most recent outing.
The floodgates opened soon after as Mbappe broke his goalscoring duck with the opener against Michel Der Zakarian's men, who then went on to concede three goals within the space of four minutes as Neymar, Mauro Icardi and Mbappe all struck in the second 45.
Montpellier were already up against it with 11 men on the field, and having also lost Florent Mollet to injury in the first half, their dismal evening in the capital epitomised their form over the past month.
La Paillade are now winless in seven matches - losing five of them - and as the only side in the top 15 without a single win from their last five, they have now slipped to 11th in the rankings ahead of the visit of Lens.
Der Zakarian has witnessed his ageing defence - marshalled by 43-year-old Hilton, 35-year-old Daniel Congre and 30-year-old Pedro Mendes - ship 18 goals in their last seven matches, and they are still waiting for their first clean sheet of the season on home soil.
Lens were never expected to be challenging for a spot in continental competition having just returned to the big time, and while they are still in with a shout of a top-six finish, a below-par performance against Nice did them no favours last weekend.
Once again, Lens' inconsistency has harmed their chances of a surprise appearance in Europe, but they are only five points off the pace as things stand, and Haise's men could temporarily rise as high as sixth this weekend if they win and Lyon beat Bordeaux on Friday night.
Sang et Or have only suffered two defeats from their last seven away from home - keeping a clean sheet on four occasions during that run - and there is certainly reason for optimism as they prepare to do battle with a Montpellier side plagued by injuries and suspensions.
However, Lens were the last team whom Montpellier managed to beat in the league, as Der Zakarian's men won 3-2 on unfamiliar territory last month.
Montpellier HSC Ligue 1 form: DLLDLL
Lens Ligue 1 form: WLLDWL
Omlin has been handed a two-game suspension for his red card against PSG, meaning that Dimitry Bertaud - who did not perform badly whatsoever after his introduction - will have the chance to impress in between the sticks.
The ankle injury that Mollet suffered in Friday's thrashing is not thought to be serious, but he remains doubtful for this game, while Teji Savanier's suspension opens up a spot for Joris Chotard or the returning Jordan Ferri to deputise in the engine room.
Star striker Andy Delort sustained a thigh problem before the trip to the champions, but there is hope that the 29-year-old could return in time to face Dijon next weekend.
Montpellier HSC possible starting lineup:
Bertaud; Souquet, Mendes, Congre, Hilton, Oyongo; Sambia, Ferri, Chotard, Ristic; Laborde
Lens possible starting lineup:
Leca; Medina, Fortes, Haidara; Clauss, Cahuzac, Fofana, Boura; Kakuta; Sotoca, Ganago
We say: Montpellier HSC 1-2 Lens
Only bottom two sides Nimes (41) and Lorient (40) have shipped more goals than Montpellier (39) so far - a statistic which bodes well for Gael Kakuta and co this weekend. The hosts will continue to struggle for goals at the correct end of the pitch in the absence of Delort, and even though Lens still have problems of their own to iron out, we are backing the visitors to take the spoils and pile more misery on Der Zakarian.