World champion Lewis Hamilton saw Max Verstappen top the times in Formula One testing on Sunday and predicted the Dutch star's Red Bull team will be "a different animal" when the season starts in two weeks' time.
Verstappen, who was third behind Hamilton and the Briton's Mercedes teammate Valtteri Bottas in the 2020 championship, timed a best lap of 1:28.960 on Sunday.
That proved to be the fastest time of the three-day session.
However, rookie Yuki Tsunoda, the first Japanese driver to compete in Formula One since Kamui Kobayashi in 2014, also laid down a marker.
His time on Sunday of 1:29.053 in his AlphaTauri was the second best overall of the week.
Verstappen had also topped the charts on Friday on the opening day at the dusty Sakhir circuit which will also stage the season opener on March 28.
"They are looking strong," said seven-time champion Hamilton.
"They're going to be a different machine or animal this year with, I think, a really good, strong line-up for two drivers and a really good car."
However, Hamilton insisted he was unconcerned as Verstappen had won the last race of 2020 in Abu Dhabi and had momentum on his side.
"Having seen them winning the last race you can only assume they're going to be right there if not at the front, at the first race.
"It's going to be a great, long battle with them through the year," he added.
Verstappen, too, was keen to douse expectations that this could be the year that Red Bull break Mercedes' stranglehold.
"I don't think we are the favourites," Verstappen said.
Carlos Sainz, in a Ferrari, Alfa Romeo's Kimi Raikkonen and Hamilton rounded out the top five on Sunday in what also proved to be their top times of the week.
Third and final day times:
1. Max Verstappen (NED/Red Bull-Honda) 1:28.960 (64 laps), 2. Yuki Tsunoda (JPN/Alpha Tauri-Honda) 1:29.053 (91), 3. Carlos Sainz (ESP/Ferrari) 1:29.611 (79), 4. Kimi Raikkonen (ITA/Alfa Romeo-Ferrari) 1:29.766 (166), 5. Lewis Hamilton (GBR/Mercedes) 1:30.025 (54), 6. George Russell (GBR/Williams-Mercedes) 1:30.117 (158), 7. Daniel Ricciardo (AUS/McLaren-Mercedes) 1:30.144 (76), 8. Sergio Perez (MEX/Red Bull-Honda) 1:30.187 (49), 9. Fernando Alonso (ESP/Alpine-Renault) 1:30.318 (128), 10. Charles Leclerc (MON/Ferrari) 1:30.486 (80), 11. Lando Norris (GBR/McLaren-Mercedes) 1:30.661 (56), 12. Pierre Gasly (FRA/Alpha Tauri-Honda) 1:30.828 (76), 13. Esteban Ocon (FRA-Alpine/Renault) 1:31.310 (61), 14. Nikita Mazepin (RUS/Haas-Ferrari) 1:31.531 (67), 15. Mick Schumacher (GER/Haas-Ferrari) 1:32.053 (78), 16. Valtteri Bottas (FIN/Mercedes) 1:32.406 (86), 17. Sebastian Vettel (GER/Aston Martin-Mercedes) 1:35.041 (56), 18. Lance Stroll (CAN/Aston Martin-Mercedes) 1:36.100 (80)