Novak Djokovic blunted the power serving of South African Kevin Anderson to reach the fourth round of the Indian Wells ATP tournament on Monday, while Mardy Fish was upset by Australian qualifier Matthew Ebden. World number one Djokovic, who beat Spaniard Rafa Nadal in last year\'s final at Indian Wells, broke the towering Anderson twice in a marathon opening set and once in the second to triumph 6-2 6-3 in one hour, 37 minutes. \"It was a very close match,\" the Serb said in a courtside interview after breaking Anderson in the sixth and eighth games to win the first set in just under an hour. \"The scoreline does not reflect how close it was, especially the style of the match. In most of our matches ... the first set goes on for half an hour or more. I was fortunate to hold that break and I returned well today.\" Djokovic lost to Anderson when they first met at the 2008 Masters Series event in Miami and, despite winning their next three encounters without losing a set, he had expected a tough challenge on Monday. \"He\'s very aggressive on the return games and he has a great serve, as you can imagine for his height,\" said the Serb. \"So I had to return well. I had to just be patient, and wait for my chances. I didn\'t serve well in the opening set ... but then I served well and put a lot of pressure on him. So I\'m really happy with this win today. It wasn\'t easy to expect to win.\" Djokovic, who won his fifth grand slam crown at the Australian Open in January, fired down five aces while the six-foot eight-inch (2.03 metres) Anderson delivered seven, but the South African won only 41 per cent of his second serves. Successful venue \"This is one of my most successful tournaments,\" added Djokovic, who was champion here in 2008 and again last year. \"I love coming back to the desert.\" Djokovic will next meet Pablo Andujar, who advanced with a 7-6 6-4 win against fellow Spaniard Albert Ramos. Fish, runner-up here in 2008, lost to South Africa-born Ebden in a match where the American was slapped with a hindrance call in the second set after he shouted \"Come on\" during a rally. \"First off, it was totally my fault,\" said Fish, who was penalised in the ninth game before being broken to trail 4-5. \"I made a mistake, and I would have been totally fine with playing a let on it. \"I was just trying to fire myself up, to be honest with you,\" he added of his yell after hitting an attempted volley winner. \"For him to get that on one bounce was an amazing get.\"