Kimball, who switched from Chip Ganassi Racing-Honda after seven seasons to join new IndyCar team Carlin-Chevrolet for 2018, clocked a 179.797mph lap on his eighth of 52 tours of the 1.022-mile oval.

Dixon was just 0.0908sec slower – although that equates to 0.794mph – while another ex-Ganassi driver, Tony Kanaan, was third for AJ Foyt Racing-Chevy.

Alexander Rossi was again fastest Andretti Autosport-Honda driver, while Gabby Chaves gave Harding Racing-Chevy a nice boost with P5.

Josef Newgarden was fastest of the Team Penske-Chevys, but teammates Simon Pagenaud and Will Power – despite being only 12^th and 16^th on the speed charts – were arguably even more impressive.

The 2016 and 2014 champions were able to turn 172mph laps more than 40 laps into their runs, despite tire life being a big question mark this year, given the removal of 1200lbs of downforce for this track. Pagenaud looked particularly assertive in traffic, while Power was the hardest-working driver of the evening, turning 99 laps.

Ryan Hunter-Reay and Marco Andretti were seventh and eighth fastest, with Rahal Letterman Lanigan Racing duo Graham Rahal and Takuma Sato completed the Top 10.

Foyt’s rookie Matheus Leist pulled off some alarmingly late passes but kept it on track, while Spencer Pigot had the only wall-scrape of the evening after being wrong-footed by a pass from Dixon.

Fastest trap speed was 192.372mph, shared by Kanaan and Rossi.

IndyCar Phoenix, final practice

Cla	#	Driver	Laps	Time	Gap	Interval	Mph
1	23	Charlie Kimball	52	20.4631			179.797
2	9	Scott Dixon	56	20.5539	0.0908	0.0908	179.003
3	14	Tony Kanaan	65	20.5871	0.1240	0.0332	178.714
4	27	Alexander Rossi	74	20.6425	0.1794	0.0554	178.234
5	88	Gabby Chaves	77	20.7698	0.3067	0.1273	177.142
6	1	Josef Newgarden	95	20.7862	0.3231	0.0164	177.002
7	28	Ryan Hunter-Reay	61	20.8063	0.3432	0.0201	176.831
8	98	Marco Andretti	87	20.8105	0.3474	0.0042	176.795
9	15	Graham Rahal	82	20.8269	0.3638	0.0164	176.656
10	30	Takuma Sato	95	20.8481	0.3850	0.0212	176.477
11	20	Ed Carpenter	61	20.8508	0.3877	0.0027	176.454
12	22	Simon Pagenaud	95	20.8563	0.3932	0.0055	176.407
13	21	Spencer Pigot	44	20.9031	0.4400	0.0468	176.012
14	5	James Hinchcliffe	66	20.9412	0.4781	0.0381	175.692
15	4	Matheus Leist	88	20.9416	0.4785	0.0004	175.689
16	12	Will Power	99	20.9511	0.4880	0.0095	175.609
17	59	Max Chilton	74	20.9733	0.5102	0.0222	175.423
18	6	Robert Wickens	79	20.9759	0.5128	0.0026	175.401
19	26	Zach Veach	90	21.0036	0.5405	0.0277	175.170
20	10	Ed Jones	71	21.0332	0.5701	0.0296	174.923
21	18	Sébastien Bourdais	58	21.1308	0.6677	0.0976	174.116
22	32	Kyle Kaiser	70	21.1487	0.6856	0.0179	173.968
23	19	Pietro Fittipaldi	66	21.3601	0.8970	0.2114	172.246