Who are you? Guide to top seeds` rivals at 2016 US Open

Listing of four favourites and their opponents.

New York: We look at the players tasked with facing four of the favourites in the first round of the US Open which gets underway at Flushing Meadows on Monday (x denotes seed):

NOVAK DJOKOVIC (SRB x1) vs JERZY JANOWICZ (POL)

Career head to head: First meeting

- At 6ft 8ins (2.03m) it`s hard not to miss the giant Pole on the grounds but a knee injury means he has been absent from the tour so long that he`s played just one top event all year, the Australian Open in January. Now ranked 228, Janowicz reached a career high 14 in 2013 and was a Wimbledon semi-finalist in the same year. He has played only six singles matches this year.

Janowicz best US Open performance: 2nd rd, 2014

ANDY MURRAY (GBR x2) vs LUKAS ROSOL (CZE)

Career head to head: Murray leads 2-0

- The 31-year-old Czech is ranked a modest 82 in the world but is no shrinking violet. Famously defeated Rafael Nadal in the first round of Wimbledon in 2014. There is bad blood between him and Murray ahead of their Tuesday meeting in New York -- when they last met in Munich in 2015, Rosol shoulder-barged the British player at a changeover while Murray described the Czech as the most-hated man in the sport.

Rosol best US Open performance: 2nd rd, 2015

RAFAEL NADAL (ESP x4) vs DENIS ISTOMIN (UZB)

Career head-to-head: Nadal leads 4-0

- Russian-born Istomin, 29, is ranked 107 and lost to Nadal at the US Open in the second round in 2010. Istomin can be dangerous on his day -- at Wimbledon this year, he made the third round seeing off Kevin Anderson and Niclolas Almagro on the way. However, he hasn`t won a tour-level match since then while his last appearance, at the Olympics, resulted in a first round exit.

Istomin best US Open performance: 4th rd, 2013

SERENA WILLIAMS (USA x1) vs EKATERINA MAKAROVA (RUS)

Career head-to-head: Williams leads 4-1

- Tough opener for the six-time champion despite the American winning two clashes at the US Open -- in 2012 and in the semi-finals in 2014 against the Russian. Makarova shocked Williams in the fourth round of the Australian Open four years ago. The 28-year-old Russian left-hander is ranked at 36, having been as high as eight last year. She comes into New York having won a gold medal alongside Elena Vesnina in the women`s doubles at the Rio Olympics.

Makarova best US Open performance: Semi-finals, 2014