The heavy rain confined all 20 drivers to their garages for the opening 45 minutes of Free Practice 2, but once conditions finally improved, it was Mercedes’ Lewis Hamilton who left it late to top the timesheet, snatching the number-one spot from Toro Rosso’s Pierre Gasly.
Hamilton waited until the final 10 minutes of this 90-minute session to take to the track, but when he did, he showed pace on his intermediate tyres to finish 1.012s ahead of Gasly, who enjoyed a promising second practice in tricky conditions.
Red Bull’s Max Verstappen, another driver to wait until the latter stages to run, came home third in Austin, just under two seconds quicker than his nearest rival, McLaren’s Fernando Alonso, while Renault’s Nico Hulkenberg had to settle for fifth.
Gasly’s team mate Brendon Hartley finished sixth ahead of Sauber’s Marcus Ericsson and McLaren’s Stoffel Vandoorne, but there were surprise runners in ninth and tenth, with Kimi Raikkonen getting the better of Ferrari team mate Sebastian Vettel.
Hartley and McLaren’s Stoffel Vandoorne – both of whom sat out Free Practice 1 – were the first to take to the track on the wet rubber, and they were soon followed by Raikkonen, Gasly, Williams’ Sergey Sirotkin and the two Sauber cars of Charles Leclerc and Ericsson.
It was Gasly who led the way for most of the session, but then a late of flurry of action saw the times continue to tumble – and it was Hamilton who ultimately finished top of the order for the second successive time on Friday.
So what did we learn? Not much to be honest, with 16 drivers getting laps under their belt - and similar conditions are expected for FP3 and qualifying on Saturday. But with the Grand Prix set to completed in dry conditions, it's certainly going to be an entertaining weekend!