The Saints, Premiership semi-finalists last term, began the campaign with victory over Gloucester but then suffered four consecutive defeats as they felt the absence of several key players on duty at the World Cup in New Zealand.
The losing sequence was ended with a comprehensive win over Exeter and Mallinder's side backed that up with LV=Cup successes over Saracens and the Ospreys.
The win over the Welsh region saw the England contingent of Ben Foden, Chris Ashton, Courtney Lawes, Dylan Hartley and Tom Wood all return to club colours, and Mallinder admits that strength in depth has made for some tough decisions.
"Selection has been very difficult this week," he told SaintsTV.
"We had a difficult start to the season but we've started slowly to turn it around. We had a good display against Exeter, a good display against Saracens a couple of weeks ago and then we carried that on against the Ospreys. With all the lads back from international duty and others back from injury, it's given us some good choices."
The Red Rose brigade, plus Tonga prop Soane Tonga'uhia and Russia wing Vasily Artemyev, have all been handed starting roles against the Falcons and Mallinder wants to see his side climb away from their lowly ninth position, but has warned his side to expect a stern examination despite the visitors being rooted to the foot of the standings.
"We're not happy about where we are and we need to make sure it's all about Saturday and winning against Newcastle. We're ninth in the table and they're twelfth, and we're desperate for wins and for points," he said.
"Newcastle are going to come down here and give it everything they've got. We know that they've come down here in recent years, given us frights and won here. They've got some good players and we've got to make sure we're at our very best."
Newcastle boss Alan Tait, meanwhile, has rung the changes with fly-half Jimmy Gopperth and centre Corne Uys, coming into a reshuffled backline which sees Luke Eves move on to the wing and Jeremy Manning to full-back. Grant Shiells, Joe Graham and Euan Murray all start in the front row, while lock Tim Swinson and flanker Will Welch also return.
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