Rohan Dennis and Richie Porte lost time on the second stage of the Tour Down Under.

Dennis, along with Team Ineos teammate Luke Rowe, suffered a flat tire with 20 km to go. Porte went down in a crash that involved about 30 riders and partially blocked the road before Flame Rouge as the peloton fought for position.

Porte suffered a graze to his left knee but was uninjured. Simon Yates (Mitchelton Scott) suffered a severe injury to his left knee.

Elia Viviani suffered road rash over most of her upper body. She underwent tests and treatment at the hospital, and although fractures were ruled out, it may be difficult for her to continue racing.

"Everything happened right in front of me and I had nowhere to go. I could see this coming and it was a nervous finale. It wasn't a hard day, so I wasn't surprised when I crashed," Porte said after the stage.

Porte did not panic after the crash. He knew that the crash happened in the last 3km and that he would be awarded the same time as the stage winner.

"I knew that, but still, if I was hampered by the crash, I think there are rules. I rode with Lopez to the finish," Porte said."

Porte was unable to fight for the stage win and the valuable 10, 6, and 4 second time bonuses given to the top three. His biggest rival and two-time winner Daryl Impey (Mitchelton-Scott) earned a six-second bonus for finishing second behind Caleb Yuan (Lotto-Soudal).

Thanks to the bonus seconds he took away in the intermediate sprint of stage 1, Impey now leads Porte and the other overall rivals by 10 seconds.

Porte, however, is confident that this year's Tour Down Under will not be decided by time bonuses.

"Daryl is obviously in good shape, he was second in today's stage, so he's a bit ahead, but tomorrow it's a different finish," Porte hinted about the third stage, which ends with a climb to Paracombe.

"I think it will be difficult this year. Mitchelton's run has the team to do what they are doing. Darryl is obviously in great shape, so it makes sense to support him. Darryl has won this race twice, so he's probably the biggest threat."

Rohan Dennis hugged Lowe after the finish to thank the Welshman for bringing him back to the peloton after he suffered mechanical problems.

"Luke helped me get back in. He sacrificed his leadout for Chris Lawless. Having this kind of support gives me a lot of confidence for the coming races," said Dennis, whose chase to the peloton was a confirmation of his fitness ahead of Thursday's crucial finish to Paracom.

"I was definitely going to come back, but it depends on how hard you work. I actually felt pretty good up there. I'm not going to say I'm going to blow everyone's doors off at Paracom, but it felt good to recover at the finish," he said.

With the addition of Paracombe, this year's Tour Down Under is likely to result in punchers like Daryl Impey struggling to stay under attack on the steep climbs and at the top of Willunga Hill on the final stage.

"When Richie won Paracom in 2017, he was about 20 seconds ahead of everyone else. When Richie won Paracom in 2017, he was about 20 seconds ahead of everyone else.

"If he wins Paracom, I think it's going to be pretty hard for him to win overall.