California - World No 1 Novak Djokovic stayed up late to book a quarter-final berth at the Indian Wells Masters early on Thursday, polishing off American Sam Querrey in straight sets around 02:00.
The Serbian star beat American Querrey 6-0, 7-6 (8/6) in a match that didn't get on court until after midnight thanks to some lengthy matches in the Wednesday day session.
Djokovic, whose two titles this year include a fourth Australian Open crown, stretched his match winning streak to 21 - dating back to a loss to Querrey at the Paris Masters on October 31st of last year.
He is 16-0 in 2013, a run that included a fourth Australian Open title and a title in Dubai.
After waiting at the venue for six hours, Djokovic got right down to business, pocketing the first set in 22 minutes.
He appeared to be on his way when he broke Querrey in the fifth game of the second frame, but the American broke back in the next game to get the set back on serve.
Djokovic had a chance to break in the 11th game, after Querrey served up two double faults, but the American saved the break point with an ace and finally held on his fourth game point.
They went with serve to the tiebreaker, with Djokovic racing to a 5-1 lead. Again Querrey rebounded, closing the gap to 5-4 with a service winner.
Djokovic gave himself a match point on his own serve with a blistering deep forehand volley for 6-4, but on the next point he was off-target with a backhand.
He got another chance after a wayward forehand from Querry gave him a 7-6 lead and Djokovic got another chance after Querrey sent a forehand wide to give the Serbian a 7-6 lead, and Djokovic claimed the match when the American netted a backhand.
"First of all thank you all for staying," he told the crowd of a few hundred who hung on to the bitter end. "It's been a very long day."
After starting the match "incredibly well" Djokovic said, he had to work to keep his poise when he gave back the break in the second set.
"I was trying to compose myself," he said. "It was very frustrating waiting the whole day ... I was really frustrated, but I was trying to hold my emotions."
In the quarter-finals he'll face French eighth seed Jo-Wilfried Tsonga, a 4-6, 7-5, 6-4 winner over Canadian Milos Raonic.
Results on Wednesday from the eighth day of the ATP Masters and WTA BNP Paribas Open (x denotes seeded player):
Men
Fourth round
Jo-Wilfried Tsonga (FRA x8) bt Milos Raonic (CAN x17) 4-6, 7-5, 6-4
Kevin Anderson (RSA) bt Gilles Simon (FRA x13) 6-3, 1-6, 6-4
Tomas Berdych (CZE x6) bt Richard Gasquet (FRA x10) 6-1, 7-5
Roger Federer (SUI x2) bt Stanislas Wawrinka (SUI x18) 6-3, 6-7 (4/7), 7-5
Andy Murray (GBR x3) bt Carlos Berlocq (ARG) 7-6 (7/4), 6-4
Juan Martin del Potro (ARG x7) bt Tommy Haas (GER x19) 6-1, 6-2
Rafael Nadal (ESP x5) bt Ernests Gulbis (LAT) 4-6, 6-4, 7-5
Novak Djokovic (SRB x1) bt Sam Querrey (USA x23) 6-0, 7-6 (8/6)
Women
Quarter-finals
Maria Kirilenko (RUS x13) bt Petra Kvitova (CZE x5) 4-6, 6-4, 6-3
Maria Sharapova (RUS x2) bt Sara Errani (ITA x6) 7-6 (8/6), 6-2