Brutal conditions took their toll as Olympic great Drew Ginn and partner Joshua Dunkley-Smith finished only fifth in their men's coxless pairs heat on the opening day of the national rowing championships. Ginn and Dunkley-Smith have formed an impressive combination since teaming up in December, winning state titles in both NSW and Victoria last month. But Ginn, an Olympic champion in the coxless pair in 2004 and 2008, admitted the blustery, extremely hot conditions at West Lakes in Adelaide got the better of them on Monday. They must now post a top-two finish in the repechage on Tuesday if they are to qualify for the final. "Rowing out there today that was something else, it was just for survival I guess," said Ginn. "But for us I don't think it was a reflection of where we're at at all. We didn't really adjust to the conditions. "If we perform as we've been racing (previously) and as we know we can, there's no reason why we won't win the repecharge." Ginn said their new partnership had been improving all the time. "Things are going well with us, I think the more time we spend in the boat the better we're getting," he said. "I think as the week goes on we'll show a lot better racing." Victorian pair William Lockwood and John Linke won the heat while Brodie Buckland (NSW) and Tom Larkins (VIC) took out the other. Defending champion Chris Morgan (SA) won his heat of the men's single scull in the day's fastest time of 8:12.97. Tasmanian's Kerry Hore produced the quickest time in the women's single scull heats, clocking 7:40.82. Angela Habashy AAP