Rea followed up his victory in Saturday’s race with another terrific effort in the Superpole event, which he won by 2.1 seconds from Chaz Davies (Aruba.it Ducati).
Davies’ Ducati team-mate and championship leader Alvaro Bautista competed the podium places in third, six seconds back, as Rea clawed back some more vital points in the title race.
Michael van der Mark finished fourth ahead of his Pata Yamaha team-mate Alex Lowes, while Leon Haslam finalised the first six on the second of the factory Kawasaki machines.
Summarising his weekend, Rea said he never stopped believing that he would soon be back on the top step.
“It was a really positive weekend, to get my feeling with the bike here and be able to really get the maximum out of it. To pick up two race wins makes me really happy,” he said.
“I want to thank all the team for always believing and keeping on pushing. We never stopped believing that this weekend was a perfect opportunity for the chance to win.
“With our form here in the past, the way our bike works here and the way I ride - it was our chance. So we had to take it and I did, in both races. That was positive but unfortunately race three was cancelled because of the weather which came in. I completely understand and I am sure we will get our chance again.”
Ex-MotoGP rider Bautista had won the first 11 races in a row to stamp his authority on the championship but he was unable to add to his tally in Ducati’s backyard at Imola, where the Spaniard was racing for the first time.
He how leads the series by 43 points after the opening five rounds from Rea, who is bidding to win the title for an unprecedented fifth consecutive time in 2019.
Heavy rain forced the cancellation of race two on Sunday, with the organisers erring on the side of safety following discussions with the riders.
Round six of the championship will be held at Jerez in Spain from June 7-9.