Lewis Hamilton is disappointed with Mercedes' upgrade after it falls short of his expectations.

After finishing fifth in qualifying behind the Ferraris and Red Bulls, Lewis Hamilton admitted he was "expecting a lot more" from the upgrades Mercedes brought to the United States Grand Prix.

Mercedes has had a disappointing season under F1's radical new design regulations for 2022, with their eight-year constructors' championship streak set to end as they remain winless with four races remaining this season.

Hamilton appeared to be making the most of his team's significant upgrades, which focused on the floor and rear wing, as he outpaced the Red Bulls on the opening runs of qualifying, despite remaining behind both Ferraris.

He was unable to maintain that pace on the crucial final lap, falling behind world champion Max Verstappen and teammate Sergio Perez, finishing nearly six tenths behind polesitter Carlos Sainz.

"It wasn't the first sector for me; it was the last sector," Hamilton explained. "But that was a really difficult Qualifying session."

"I had been feeling so optimistic all weekend; the car setup felt good, everyone back at the factory worked so hard to bring an upgrade, and I was hoping we'd be much closer than we were."

"I don't know if it was because the temperatures dropped or the wind or what, but the car was such a handful all of a sudden and not like any other time we had driven it, but I was expecting a lot more."

Despite his disappointment, grid penalties for Perez and Charles Leclerc, who qualified second behind his Ferrari teammate Sainz, mean Hamilton will start third, with George Russell on the second row alongside him.

Mercedes has been stronger in races than in qualifying this season, but Hamilton isn't confident of challenging Sainz and Verstappen for the win on Sunday.

"These guys are a lot faster, especially Red Bull on the straight," added the seven-time world champion.

"I believe we can keep up with them through the corners, but on pure pace, no matter what upgrade we bring, the gap remains the same."

"That is undoubtedly difficult for everyone on the team who is working so hard, but we will give it our all tomorrow."

Russell and Wolff forecast a 'exciting' race.

Despite Hamilton's dissatisfaction, Russell and Mercedes team principal Toto Wolff had more positive reactions to the upgrade.

Russell believes that the high level of tyre degradation he anticipates in Sunday's race will make for an exciting race.

"It's rare that a driver goes into a weekend more excited about the race than qualifying," Russell said.

"There's a lot of tyre degradation and strategy options, and I think that's what makes these F1 races exciting. If it's a simple one-stop shop, it's the same for everyone, and it's not particularly exciting."

Wolff was pleased with the update, claiming that it had put Mercedes within striking distance of their competitors on a track that they did not consider to be one of their strongest.

"I believe the update is effective," Wolff said.

"We had a three-tenths faster lap in us, but the car was so difficult to drive."

"I believe we will be involved in some exciting games tomorrow."

"I think Austin was never great for us in the past, but it worked well here." We're six tenths of a tenth off, it could have been three, so yes [it worked]."