AVONDALE, Arizona – After two days and 12 hours of testing involving 23 Verizon IndyCar Series entries at ISM Raceway, a couple things are clear: teams learned more about the performance of the 2018 car and Rahal Letterman Lanigan Racing established the early advantage.

RLL drivers Takuma Sato and Graham Rahal set the fastest lap in each of the four three-hour sessions spread over Friday and Saturday. Sato, in the No. 30 Honda, recorded the best lap of the Phoenix open test in Saturday’s final practice, at 189.855 mph (19.3790 seconds). The reigning Indianapolis 500 winner sat atop the speed chart in three of the four sessions, with Rahal leading the other practice in the team’s No. 15 Honda.

PHOENIX OPEN TEST AT ISM RACEWAY: Final practice results; Combined practice results

“The open test was very successful, I would say,” Sato said. “Lots of things done and lots of things to be tried, and I think over the course of two days we learned a lot. Great car, definitely more exercise for the drivers, definitely busier with low downforce.

“We did qualifying simulations and race traffic runs. I think the Rahal Letterman Lanigan team is really strong, so I’m really looking forward to two more road course tests and hopefully we’ll be ready for St. Pete (the season opener next month).”

More than 6,000 laps were completed in the two-day test on the 1.022-mile oval. Toss in another 617 laps turned by ISM Raceway newcomers on Thursday’s rookie day, and the 23 drivers totaled nearly 6,800 miles of valuable track time to get better acquainted with nuances of the 2018 car featuring the universal aero kit for all competitors.

Team Penske’s Will Power posted the second-fastest lap in the final practice to rank second on the combined sheet for all practices. The 2014 Verizon IndyCar Series champion toured the oval at 189.769 mph (19.3878 seconds) in the No. 12 Verizon Team Penske Chevrolet.

“Really enjoying this car; the 2018 car is awesome,” Power said. “Our No. 12 Verizon Chevy’s been pretty good the whole time. We're really in a good window, I feel like. So are a lot of people, by the look of it.”

Tony Kanaan, entering his 21st season racing Indy cars and first with AJ Foyt Racing, was third in the last practice and overall with a lap of 189.632 mph (19.4018 seconds) in the No. 14 ABC Supply Chevrolet.

“It was a good couple of days,” said Kanaan, a two-time winner at ISM Raceway including his championship season of 2004. “We tried to run in traffic a little bit at the end. It's going to be tricky, it's definitely going to be tricky. We are still learning about the downforce but, all in all, I think it was a positive test for us.

“We learned a lot, we didn't have any major problems, which that’s what we're looking for at this team right now is just to build. Build confidence and build momentum.”

Kanaan’s teammate, Matheus “Matt” Leist, didn’t fare as well. The rookie brushed the wall three times in the No. 4 ABC Supply Chevy over the course of the day, following a spin without wall contact on Friday. Despite that, the 19-year-old Brazilian was fastest of the five rookies participating at 187.431 mph.

The only incident of significance over the two days involved four-time series champion Scott Dixon, whose No. 9 PNC Bank Chip Ganassi Racing Honda made contact with the Turn 2 SAFER Barrier with 30 minutes remaining in final practice. Dixon was uninjured.

“We were just in traffic there,” Dixon said. “It was our second or third lap out of the pits. A couple of the Andretti cars got by and were a little bit slower. I got low in (Turns) 1 and 2, touched the throttle and had a bit of a run and lost the rear. Kind of late in the corner, but just touched with the rear and bent the left rear suspension.”

Josef Newgarden, the 2017 Verizon IndyCar Series champion sporting the No. 1 on his car this year, was fourth on the speed chart with a lap of 189.399 mph (19.4257 seconds) in his Hitachi Team Penske Chevrolet.

Drivers now have a month to prepare in private team testing before the 2018 season opener, the Firestone Grand Prix of St. Petersburg from March 9-11. It is the first of 17 races on this year’s calendar. The race airs live at 12:30 p.m. ET March 11 on ABC and the Advance Auto Parts INDYCAR Radio Network.

The Verizon IndyCar Series returns to ISM Raceway for the Phoenix Grand Prix on April 6-7. The race weekend will commemorate the 25th anniversary of Mario Andretti’s final Indy car win, in 1993 at the oval in the desert. The race airs live at 9 p.m. ET on NBCSN and the Advance Auto Parts INDYCAR Radio Network.