Beaten Andy Murray was at a loss to explain his Indian Wells woes after a shock second-round defeat against Canada's Vasek Pospisil.

The Scot's best showing in California came in 2009 as a runner-up to Rafael Nadal and this 6-4, 7-6 (7/5) defeat was his first in five meetings against the world No.129.

As such, Indian Wells and Monte Carlo remain the two ATP Tour 1000 events to elude him.

"I don't know exactly why it is, because in practice I normally play pretty well," he said of his struggles in California. "Some years I've played well. Some years it just hasn't quite happened for me.

"I don't know exactly why that is. I don't know if it's the conditions. I really don't know why I haven't played my best here over the years."

Murray, who claimed his maiden title of 2017 at the Dubai Duty Free Championships last week, was sluggish from the start in the BNP Paribas Open clash.

The 29-year-old was broken four times in total by Pospisil, who celebrated his biggest-ever win on the ATP Tour and declared it as his finest hour.

"He's always played that way, maybe he was doing it better this evening," Murray said of an opponent who needed an hour and 50 minutes to beat him.

"He was maybe a bit more solid from the back, a bit more consistent from the back of the court.

"That allows you and gives you more opportunities to come to the net. If you're making mistakes in the first three, four shots of the rally, it's not easy to come in on the correct ball.

"When you're a little bit more solid, you can be patient and wait for the right shot to come in on."

And Pospisil duly did. With four match points to play with, the Canadian converted the fourth to secure a place in round three at the expense of the top seed.

"It's an amazing feeling," said Pospisil. "Obviously, it happened pretty quick. I feel like I'm on a comeback trail. I had a tough year last year for many, many different reasons.

"I feel the last couple months I really found my hunger and my motivation to be back on the court training hard again.

"I felt like a big result was coming. Obviously to beat the No.1 player in the world is incredible. It's the biggest win of my career. I'm thrilled."

Former world No.1 Caroline Wozniacki, meanwhile, thinks Maria Sharapova's wildcard for the Porsche Grand Prix in Stuttgart next month is "disrespectful".

Sharapova's 15-month ban for taking meldonium ends on April 26 and the Stuttgart event starts on the 24th.

As such, Sharapova – who will return to the sport without a world ranking – will not be allowed at the venue until her ban has passed.

Wozniacki is happy to see the five-time grand slam winner returning to the Tour, but does not believe it should be in Stuttgart.

Speaking at the BNP Paribas Open in Indian Wells she said: "First of all I think she's a good draw for tennis, women's tennis in general. But two, I think it's questionable allowing – no matter who it is – a player that is still banned to play a tournament that week.

"From the tournament side I think it's disrespectful to the other players and the WTA. But it is what it is. Obviously rules are twisted and turned in favour of who wants to do what.

"I think everyone deserves a second chance and I think she's going to come back and fight her way back. I'm sure she's going to play well. But at the same time, I feel when a player is banned for drugs, I think someone should start from the bottom and fight their way back."