The triumph completed the Bora-Hansgrohe rider's set of Grand Tour stage wins following victories during the 2020 Tour de France and last year's Giro d'Italia.

He emerged strongest from an eight-man break on a tough final climb to Collado de la Cruz de Caravaca.

Despite poor weather in Cartagena, he was able to cross the line for victory after 4hours 28min 59sec as he won the 184.5-kilometre stage.

Team Jayco Alula's Italian rider Matteo Sobrero was not too far behind as he followed suit 13 seconds later before Australian Christopher Hamilton of Team DSM-Firmenich made up the top three 1:12 off the pace.

"I'm super happy," Kämna said after his ninth career victory.

"I worked really hard the last couple of months.

"It was not always easy after the Giro, a lot of setbacks.

"But I'm so happy that I'm back on the podium and I can take this win.

"It was really tricky at the end because the climb was always going up and down and it was hard to find the moment to drop the others.

"But that moment just comes sometimes and I had a little gap to go through.

"After that it was just a fight to the end."

The challenging final stretch was neutralised by strong wins that blew throughout the stage and helped to launch multiple attacks throughout.

Team Jumbo-Visma rider Kuss has a 43-second lead over UAE Team Emirates Spanish rider Marc Soler while France's Lenny Martinez of Groupama-FDJ is 19 seconds further back in third.

Kuss' team-mate, Primož Roglič of Slovenia, gained another two seconds on Soudal Quick-Step's defending champion Remco Evenepoel and was happy with his team's performance.

"I'm happy we finished and it was not the finish completely on the top because it was quite tricky with the corners," he said.

"It was a hard climb at the end and I’ve survived [the first week]."

The race is set to take a break tomorrow in what is the first rest day before stage 10 is scheduled for Tuesday (September 10).

Racing is due to resume with a 25.8km individual time trial in Valladolid.