Al-Attiyah and Peterhansel both made inroads into Sainz's lead in the penultimate test as the Spaniard opened the stage, and they now both sit just over 10 minutes adrift.
The final Haradh - Qiddiya test on Friday was due to be contested over 374km, but construction of gas pipelines on the route has forced the organisers to slash the timed special down to 166km.
And though rally director David Castera says he believes the final stage could yet catch out competitors, neither Al-Attiyah nor Peterhansel see Sainz losing his lead.
"No, it's not possible," Toyota driver Al-Attiyah said when asked if he could yet overhaul Sainz.
"Yesterday we lost a lot of time, we made a mistake, and I knew we lost the Dakar, because to make a big mistake, navigation, it costs a lot.
"But okay, I am quite happy, you know - to have Carlos tomorrow win, [I'll be happy] for him, he did a really good job.
"I tried to win this Dakar, the first edition here in Saudi, but okay, I am happy to race with Carlos, with Stephane, these are some of the best drivers here in Dakar.
"Tomorrow it's a short stage, half the stage is cancelled. Tomorrow our goal is to catch Stephane, [he is] only six or seven seconds [behind]. The [Mini] buggy is really quite fast here in Saudi Arabia."
Peterhansel said he would be content a podium finish given the context of his late-notice co-driver change - with his wife Andrea having had to cede the role to Paulo Fiuza for health reasons.
"Four stages won in this edition and that is a good result, but not so good for the general [classification]," Peterhansel said.
"But for me it's fine. I am very happy because before I started I was not sure I could be on the podium, with the last-minute change of a new co-driver."
As he expects to be slower than Al-Attiyah on Friday given that his Mini will be the first car on the road, Peterhansel concedes it may be difficult to make up the six-second gap to the Qatari.
But this remains the target, and in the meantime the 13-time Dakar champion will be cheering on Sainz - who he's been teammates with for each of the past six editions of the marathon.
"Carlos is very fast. He has a great speed," Peterhansel said.
"Lucas [Cruz, Sainz's co-driver] made some small navigation errors, I think fewer than us, and that is why they are in front.
"We have done a great job in the team, many tests, we've shared a lot of information and we have worked a lot together and very well, and it is the reason why I am happy, even though I cannot win.
"We are very close since the Peugeot years [2015-18] and it is very nice to be teammates."