Kyrgios beats Wawrinka at Madrid tennis

Nick Kyrgios has downed Switzerland's Stan Wawrinka 7-6 (9-7) 7-6 (7-2) in a hard-fought second-round match at the Madrid Open.

Nick Kyrgios is through to the second round of the Madrid Open after a win over Guido Pella. (AAP)

Nick Kyrgios has battled hard to beat Stan Wawrinka in the second round of the Madrid Open.

The Australian took more than an hour and 40 minutes to down the fourth seed 7-6 (9-7) 7-6 (7-2).

Earlier, eighth seed Tomas Berdych of the Czech Republic downed Denis Istomin of Uzbekistan 6-3 6-3.

The 15th-seeded Roberto Bautista beat Feliciano Lopez in a tight, all-Spanish second round, 6-3 5-7 7-5