Jakob Ingebrigtsen made his first appearance of 2020 a winning one, breaking the Norwegian 5km road record in Stavanger on Wednesday (20 May).
The 19-year-old, who won 1500m and 5000m gold at the 2018 European Championships, clocked 13:28, rounded down from 13:29, to take nine seconds off the mark set by Sondre Nordstad Moen in Monaco last year.
Elder brother Henrik was second in 13:32, also inside the old record.
Fellow Norwegian Per Svela was third in the five-man field.
"First and foremost, it was great fun to get the starting bib on. I had to wake up the body a little. And as I pushed more, I didn't feel any strain." - Jakob Ingebrigtsen speaking afterwards to NRK Sport
Ingebrigtsen brothers show their class
Jakob Ingebrigtsen ended 2019 on a high by winning his fourth U20 European Cross Country title in Lisbon.
Henrik was last seen competitively in the World Athletics Championships in Doha, where the pair and middle brother Filip finished out of the medals, but the three acted as pacemakers for Eliud Kipchoge in his historic sub two-hour marathon in Vienna in October.
With the COVID-19 pandemic prompting lockdown in Norway and other countries, the Ingebrigtsens have had to wait for racing to resume.
Restrictions have eased in the last week allowing the Forus Perseløp race in Stavanger, 15km north of their hometown Sandnes, to take place.
To comply with regulations, there were several groups of runners with the elite category limited to five.
Jakob and Henrik were joined on the startline by fellow Norwegians Per Svela and Narve Gilje Nordås, and Eritrea's Zerei Kbrom Mezngi.
Henrik led from the start but the rest of the field, with the notable exception of Jakob, all had a turn at the front before the youngster wound up the pace inside the final kilometre.
Even Henrik, who is concentrating on longer distances this season, struggled to keep up as Jakob crossed the line to achieve what he had set out to do.
Henrik was second with Svela taking third ahead of Mezngi and Nordås.
It was little more than an intense training session for the Ingebrigtsen siblings with Jakob taking just 30 seconds to regain his composure and give an interview.
He told NRK Sport, "I have trained extremely well. Compared to this time last year, I must say that I have taken a step in the right direction again."
Henrik said, "The most important thing was not to go crazy compared to Jakob. I think I'm clearly fine. The body held up, and I feel I am where I should be in relation to Jakob."
The Diamond League is now scheduled to start in August, but Jakob cannot wait to compete again on the track.
He said, "I have to say that I've been fooling myself. I've been telling myself, 'Now it's not long until I run,' although I know deep down that there will probably be a while with things are as they are.
"But it motivates me to trick myself that maybe there will be a race around the corner."
Their 14-year-old sister Ingrid also ran in Stavanger, clocking 18:00 to finish seventh out of 12 all-age women runners.