Yeah, Ristic must be thrilled they are best friends.
This is from a very recent interview:
Jelena mi daje vetar u leđa!
Jelena mi je uvek davala vetar u leđa da budem još bolji na terenu. Ona je završila školovanje, osamostalila se, radi i sada je zbog prirode posla mnogo češće u prilici da bude sa mnom na turnirima, što meni baš prija. Nažalost, Novu godinu nećemo provesti zajedno jer je ona zbog obaveza oko fondacije i projekata morala da ostane u Beogradu, ali smo srećni jer smo ceo decembar proveli zajedno i napunili baterije za nove izazove.
I doubt Jelena is too bothered. It's not like she never met/meets Ana. They both attended Novak's birthday party in some restaurant in Paris in 2010 and at Wimbledon 2011, he held a barbecue at the house he was sharing with his girlfriend and team which Ana went to as well. These are two occasions we know for sure of but there were probably more. There was a totally normal reason given above for why she isn't in Perth. I don't know, I presume she feels pretty secure. As he said they were together the whole of December and there were plenty of pictures of them enjoying themselves...