Djokovic, trying to match Andre Agassi’s record of six Miami titles with his third in a row, will play Belgian 15th seed David Goffin on Friday for a berth in Sunday’s final.
The 28-year-old Serbian won his 14th consecutive match at the hardcourt event and his 28th out of 29, but needed a gritty performance after back pain began early in the second set, prompting him to have massage therapy before serving in the sixth game.
“Due to windy conditions on the court, it was hard to find a good rhythm to serve,” Djokovic said. “I had a little bit of a spasm in the back but (the trainer) did a great job and I was able to finish the match.”
Asked if he had any worries the spasms might become a long-term issue, Djokovic said: “No concerns. None at all.”
On the women’s side, reigning Australian Open champion Angelique Kerber, the second seed from Germany, and two-time Australian Open champion Victoria Azarenka of Belarus advanced to a Thursday semi-final showdown.
Both have finals wins over top-ranked Serena Williams this year, Kerber at the Australian Open and Azarenka at Indian Wells.
Berdych lost his 10th consecutive match to Djokovic, whose domination of their career rivalry reached 23-2. Berdych’s last victory over Djokovic was in a 2013 Rome quarter-final.
Djokovic blasted a crosscourt forehand winner to break Berdych for a 3-1 lead and held from there to claim the first set, in which the Czech had 21 unforced errors.
Berdych surrendered a break to open the second set but Djokovic first reached for his lower back in the next game but held and broke again to end the match.
“Overall, this is the best match I’ve played in the tournament,” Djokovic said. “I feel better than I did last year at the same stage. I’m hoping I can keep the same trajectory.”
Djokovic won his 11th Grand Slam title two months ago at the Australian Open and also has crowns this year at Indian Wells and Doha.
Goffin matched his semi-final run from Indian Wells by downing French 18th seed Gilles Simon 3-6, 6-2, 6-1.
Former world number one Azarenka defeated British 24th seed Johanna Konta 6-4, 6-2 while Kerber cruised into the semi-finals, downing US 22nd seed Madison Keys 6-3, 6-2.
The German second seed, the last of the top 12 remaining, is 1-6 lifetime against Azarenka, but won their most recent meeting in the Australian Open quarter-finals on the way to the title.
Eighth-ranked Azarenka, who won the 2009 and 2011 Miami titles, will jump to fifth in the world next week.
Azarenka could become only the third woman to win back-to-back in Miami humidity and Indian Wells desert heat after Steffi Graf in 1994 and 1996 and Kim Clijsters in 2005.
Two-time Grand Slam champion Svetlana Kuznetsova meets Swiss 19th seed Timea Bacsinszky in the other semi-final. The 30-year-old Russian has won both their previous meetings.
Andy Murray has rubbished talk of a rift with coach Amelie Mauresmo after he crashed out of the Miami Open with a three-set loss to Grigor Dimitrov.
Mauresmo watched on from a different part of the stadium to the box where the rest of Murray’s team and family were located as the world number two produced more than 50 unforced errors in a 6-7 (7/1) 6-4 6-3 loss to the Bulgarian.
Murray, who received a violation from the umpire for smashing his racket during the second set,
insisted that Mauresmo was sat elsewhere in a bid to curb his on-court tantrums.
“I’ve just been trying to find different ways to improve my focus on the court,” Murray said.
“I also did the same thing at the O2 Arena as well, so I’m trying to find different ways to improve and that’s something I’ve tested to see if that might help.
“If I’d had a falling out then Amelie wouldn’t be here at the tournament. We had dinner with all our families last night, so we certainly haven’t fallen out. It’s one of those things that when I win no one says anything about it, and then when I lose that’s an excuse. I don’t think that is the reason for me hitting 50 unforced errors in this match.”
The defeat, in which Dimitrov showed the sort of form which propelled him into the top 10 of the world rankings in 2014, brought to an end a difficult American hard-court swing of the season for Murray, who is still facing challenges of life as a new parent.
He lost to Federico Delbonis at the BNP Paribas Open in Indian Wells a fortnight ago and he has won just two ATP World Tour matches since the final of the Australian Open in January.
However, Murray’s position at No2 in the world rankings is safe for the moment, but the Scot will need to rediscover his form quickly if he is to avoid being overtaken by Roger Federer in the coming weeks.
Having lost in the Miami final to Novak Djokovic last year, Murray will see his points total drop by 555 to 7,815 when the world rankings are updated at the conclusion of the tournament next week.
That will leave him just 120 points ahead of third-placed Federer.
Few players can unite the tennis world the way Juan Martin del Potro does, as it seems everyone is rooting for the Argentine in his latest comeback attempt.
The 2009 US Open champion is three tournaments into his return from wrist surgery and he’s already made the leap from outside the top-1000 to the top-350 in the ATP rankings, thanks to a semi-final showing in Delray Beach, and second round appearances in Indian Wells and Miami. Those runs included two top-40 wins over No30 Jeremy Chardy and No39 Guido Pella.
The good news for Del Potro is that his serve and forehand appear to be as punishing as they’ve ever been. The bad news is that he seems hesitant to hit through his backhand, which requires him to utilise the left wrist which was operated on multiple times in the past 12 months. The 27-year-old has been opting for the backhand slice so far, which only requires him to use his right hand.
The obvious question is: can del Potro get back into the top-five without a solid backhand?
Someone like world No7 Tomas Berdych, who was pushed to a tiebreak in his first set against del Potro in the Indian Wells second round before he beat the Argentine in straights, questioned whether a player can be amongst the tennis elite without a strong backhand.
“When you look at the top guys, there (are) no signs of weakness from any of the sides,” Berdych pointed out.
It is true.
If you look at the players ranked in the top 30, Feliciano Lopez, the world No23, is probably the only player who regularly slices his backhand instead of hitting through it. The Spanish veteran was ranked as high as No12 in the world last season but his aggressive chip-and-charge game is not a typical one and while successful against many, it still gives him a 28.3 per cent success rate against top-10 opposition. Del Potro acknowledges that he still has a long way to go in order to stabilise his left wrist and be confident enough to hit the double-handed backhand. Would he have been better off delaying his return until he could execute it properly?
Considering how many times Del Potro has been injured and has come back to the circuit, he is the best one to judge whether this was the right moment to return.
For now, let’s just put on our “Everybody loves DelPo” shirts and enjoy having him back on tour. Time will tell if he can recover his top-five form.