Columnist Mike Holder keeps you up to date with some of the most notable headlines regarding Americans each day in Melbourne.

Soon after Alison Riske, Lauren Davis and Serena Williams notched victories on the first night, the Americans were back at it in Melbourne Park early on Tuesday. While Monday featured the top American woman, Tuesday featured the No. 1 American man.

Top-ranked American John Isner, opened his play in Melbourne on Tuesday and it became clear that he was not in peak health. In what has become a theme over the years, Isner dug himself a big hole early by dropping the first two sets against a dangerous Martin Klizan. Despite a first-serve percentage of 78 percent to go with 10 aces after two sets, the American gave away 23 points via unforced errors, clearly hampered in his movement. Meanwhile, the Slovak was able to keep pace with the big-serving Isner, nearly equaling him in aces. However, Isner faced a much bigger obstacle as an ankle injury suffered at the Hopman Cup became more evident as the match progressed. After dropping a second-set tiebreak, Isner was unable to continue, retiring at 2-6, 6-7. He will leave January with success in New Zealand and disappointment in Australia.

In the women’s draw, Christina McHale started the day off successfully for the Americans. Facing Yung-Jan Chan, she found herself in a tight first set before righting the ship to take that set 7-5. After finding her rhythm, she built upon that momentum and held off the 24 year old from Taiwan, 7-5, 6-4. McHale, who struggled with consistency in 2013, entered the Australian Open in the best shape of her career. Working with USTA trainers in the off season, she became noticeably stronger and hopes that a superior fitness level will translate to more durability and positive results on the court. On Tuesday, in extreme heat conditions, she appeared to see benefits as she fought off surges from Chan to advance to the second round.

Other Americans in early Day 2 action included Vania King, who was no match for No. 16 seed Carla Suarez Navarro as she fell in straight sets. More promisingly, the 50th-ranked Varvara Lepchenko overcame a slow start and 52 unforced errors to defeat Lesia Tsurenko of the Ukraine 2-6, 6-3, 6-4. And Bradley Klahn should take pride in winning a set against No. 22 seed Grigor Dimitrov before falling in the men’s draw.