"I think I played a solid match", said Nadal, who will face John Isner of the United States in the quarter-finals tomorrow.
The Spanish world No 1, enjoying a late-career flourish, dispatched Russia's promising Karen Khachanov 6-3 6-3 on the outside hard court in Beijing.
"Tomorrow will be a tough one against Isner".
No. 6 seed Isner thrashed world No. 54 Leonardo Mayer 6-0 6-3.
"(Pouille) played well. Very aggressive, He's serving well", Nadal said.
The 31-year-old Nadal broke Khachanov, ranked 42 in the world, in the fourth game and was never in serious trouble after that.
It looked as though Khachanov was set to give Nadal a tough time on Thursday as he came close to breaking him in the opening game.
Also, third-seeded Sorana Cirstea defeated fourth-seeded Karolina Pliskova 6-1 7-5.
He is looking to go on and make the semi-finals for the second time. But still I didn't have the control of the match for nearly all the time.
Isner won the match 7-5 6-5.
Andrey Rublev ensured a continued Russian presence in the men's draw as he sprang a surprise in fighting back to oust seventh seed Tomas Berdych 1-6, 6-4, 6-1.
World No. 1 Garbine Muguruza and reigning champion Agnieszka Radwanska are both out, leaving world No. 2 Halep as the favourite.
Garcia is in red-hot form after winning the Wuhan Open title on Saturday and has a chance of taking the final WTA Finals spot, which starts in Singapore on Oct 22.
The American struck eight aces and converted all four of his break points to earn the quarter-final clash with Nadal.