The confirmation from these two top-20 players along with participation from World No.6 Tomas Berdych and World No.9 Janko Tipsarevic have ensured that the tournament will have one of the strongest fields in its history.
Cilic, the 6ft 6inch Croatian, won the singles titles here in 2009 and 2010. He was in the 2012 field as the fourth seed but suffered a patella tendon injury, which ruled him out of the tournament as well as the season's first Grand Slam, the Australian Open.
After recovering, the right-hander gained momentum by reaching the Munich final in April this year. In July, he captured his eighth ATP World Tour title at the ATP Vegeta Croatia Open Umag.
The 24-year-old Cilic, who has begun five previous seasons in Chennai, registered his career high ATP ranking of 9 on February 22, 2010 with his best-ever performance in a Grand Slam, reaching the semi-finals in the 2010 Australian Open.
He won his first Chennai Open title in 2009, defeating India's Somdev Devvarman and followed it in 2010, beating Wawrinka in the final.
"I am delighted to be back in Chennai, especially since I could not participate in last year's event due to an injury. I have chosen to start my five previous seasons here and have had great success as a lead up to the Australian Open. It is always a pleasure to play in Chennai, a city that has grown to become a home away from home for me," said Cilic.
Wawrinka, the world ranked 17th from Switzerland, who will also be a part of this season's draw for the fifth straight year, is eyeing a winning start like the previous edition. More
