Valtteri Bottas edged out Max Verstappen to top the Practice Two timesheets and halt Red Bull's flying start to Abu Dhabi GP.
Red Bull dominated the weekend's opening session but Bottas, looking for a first win of the season at the F1 2018 finale, outpaced Verstappen by just 0.044s to set the pace for Mercedes under the Yas Marina lights.
"P2 was really good, the car felt like I could trust it and drive it the way I want," said Bottas.
"It's nice to be on top of the timesheets, but we now need to build on that, we need to try and make the right set-up changes and I also need to find more performance from myself."
When's the Abu Dhabi GP on Sky F1?
Find out more about Sky F1
Watch Sky F1 with Race Control
Daniel Ricciardo was third and a tenth of a second behind team-mate Verstappen, while world champion Lewis Hamilton finished fourth in the sister Mercedes.
"Red Bull looked quick today," stated Hamilton. "They're usually fast in practice and in the race, so I have no doubts it will be the same this weekend."
Ferrari's Kimi Raikkonen and Sebastian Vettel could only manage fifth and sixth, but it was a fiercely competitive second practice - the top six were split by just 0.333s to hint at an extremely tight final F1 weekend of the season.
"That's a really encouraging session in terms of the race," said Sky F1's Simon Lazenby.
Red Bull ahead of Ferrari
The fact Red Bull have displaced Ferrari, temporarily at least, as pre-weekend favourites Mercedes' closest challengers is especially intriguing.
"On most of the corners on the track it's working really well," said Verstappen. "I'm really happy with that."
Ricciardo added: "I'm excited. We look pretty good."
Red Bull haven't claimed an Abu Dhabi podium since 2013, while the track - featuring two long straights - would normally suit Ferrari's power-friendly package and not the Renault-powered Bulls.
"The long run pace in particular looks very good," Red Bull boss Christian Horner told Sky F1. "The chassis is working beautifully."
Ferrari are, however, expected to turn their engines up for Saturday's qualifying, which could lift their drivers into contention.
"We're not yet quick enough but hopefully tomorrow we will be," said Vettel. "I'm not entirely happy yet.
"It's going to be tough and it's going to be tight."
Romain Grosjean finished best of the rest in seventh for Haas, and both he and Renault's Nico Hulkenberg were impressively within a second of the leading time.
Fernando Alonso, preparing for what could be his last F1 race, would have also been encouraged by Practice Two, finishing 13th in a McLaren car that has been toiling at the back of the grid in recent months.
His team-mate Stoffel Vandoorne was 18th, just ahead of the Williams who propped up the timesheets.
Sky Sports F1 is the only place to watch every Formula 1 Grand Prix, qualifying and practice session live in 2018. Get Sky Sports F1.