Hamilton can win his fifth world title this weekend if he finishes eight points above Sebastian Vettel.
The Brit cruised through the first two qualifying sessions and led for the majority of the third.
But Kimi Raikkonen whipped around the track in his record time with his final attempt to put himself top of the standings.
Hamilton replied instantly as the clock ticked down to zero – before Sebastian Vettel secured the second fastest time, sneaking in ahead of his team-mate.
However, Vettel will incur a three-place grid penalty after speeding during a red flag in FP1, meaning he must fight his way from fifth place.
“That was very important. That was close…” admits Hamilton.
“I knew it was going to be quite edgy between us.
“I was adamant that I had to do a better second lap so I’m really happy with that.”
US Grand Prix qualifying results LIVE – start 10pm
(Results to follow)
Q1
Out: Vandoorne, Alonso, Stroll, Sirotkin, Ericsson
*Lewis Hamilton the fastest with Valtteri Bottas second. The pair of Ferrari’s, led by Sebastian Vettel, finished just behind.*
Q2
Out: Sainz, Magnussen, Gasly, Hartley, Verstappen
*Max Verstappen did not leave the pits because of a suspension problem. Kimi Raikkonen the quickest this time around with Sebastian Vettel second. Lewis Hamilton third.*
Q3 – top 10
Hamilton
Vettel (before three-place penalty)
Raikkonen
Bottas
Ricciardo
Ocon
Hulkenberg
Grosjean
Leclerc
Perez