It is Ankita's sixth attempt to crack the singles main draw of a Grand Slam and she is now just one win away from creating history.
Ramkumar, who made the final of the Eckental Challenger last week, lost 6-3 4-6 1-6 to his 35-year-old Russian rival.
Ramkumar Ramanathan, celebrating his 26th birthday, lost the summit clash 4-6 4-6 to Sebastian Korda, ranked 135.
The 25-year-old Ramkumar fired 12 aces and won five of seven break points on his way to the final of the Euro 88,520 event.
The 25-year-old Ramkumar was profligate as he squandered as many as seven of the eight breakpoints he earned.
Playing against world number 37 and the 2014 US Open Champion, Ramkumar played fearless brand of tennis, forcing Cilic to play his best game.
With the only ATP event in India shifting from opening week of the year to the first week of February, it is for the first time since 2003 that the tournament will not feature a single player from the
Ramkumar Ramanathan today improved his career-best rank to 168 in singles, while Sania Mirza was unchanged at number seven in the doubles.
Ramkumar, coming into Antalya Open, had won a total of three matches at that level, with his last coming in Chennai in 2016.
On Saturday, Leander Paes will look to break the record for the most number of Davis Cup doubles wins.