What turned out to be a brilliant day for Ducati saw Rinaldi and Alvaro Bautista within the same tenth of a second come the end of play, while six-time WorldSBK champion Jonathan Rea managed to split the two Aruba.it Ducati riders.

Continuing his fine form from Jerez where Rinaldi was best of the rest behind the top three from last season, the 27-year-old was far from that as he took an even bigger step forward on day-one at the Algarve International Circuit.

The Italian, who is currently in his third season with the factory Ducati team, narrowly missed out on setting a new Superbike lap record after clocking a time of 1:39.639s - the record, which is held by Rea, is a time of 1:39.610s.

Toprak Razgatlioglu was fourth fastest for Yamaha, however, the Turkish star was arguably the most consistent rider throughout the day, whilst also being the only one to set top five lap times with both his first and second R1 Yamahas.

Following their strong showing at Jerez, rookies Remy Gardner, Danilo Petrucci and Dominique Aegerter found it tougher to stay close in terms of lap times with the factory riders. 

Gardner was 12th quickest - that includes being behind some riders who used two different bikes to set lap times, while Petrucci and Aegerter were down in 20th and 21st. 

Bautista sets the pace during first session of Portimao WorldSBK test

After seeing Razgatlioglu lead for most of the morning, Bautista produced a time just two tenths shy of the existing Superpole lap record, set by Rea. 

A time of 1:39.862s was enough for the reigning world champion to hold off team-mate Rinaldi in what was a very promising start for the Ducati duo.

Just +0.020s separated Rinaldi from Bautista, while a late effort from Andrea Locatelli saw the Pata Yamaha rider leapfrog his team-mate Razgatlioglu.

In the mix for top spot early on, Rea had to settle for fifth after dropping close to four tenths down on Bautista’s time.

There were two red flags, the firft of which was due to Rea’s team-mate Alex Lowes suffering a fall at turn 10.

Unhurt from the crash, Lowes managed to resume testing aboard his second bike before a fall for Honda rider Xavi Vierge, this time at turn 13, brought out the second red flag of the morning.