Russell Knox one shot off lead at WGC-HSBC Champions

Russell Knox is yet to win on the PGA Tour

Scot Russell Knox was one shot off the lead when the third round of the WGC-HSBC Champions event in Shanghai was suspended because of darkness.

With one hole of his third round remaining, the 30-year-old is a shot behind leader Kevin Kisner, as are Dustin Johnson and China's Haotong Li.

Kisner leads on 16 under after shooting a two-under-par 70 on Saturday.

Jordan Spieth, who is hoping to return to world number one, had a nine-under 63 to move to 13 under overall.

Spieth began the day 10 shots behind Kisner, but carded nine birdies to move three adrift of his fellow American, who had his first bogeys of the week.

On a day when play was delayed because of the weather, the final group of Knox, Kisner and Branden Grace were asked on the 18th tee if they wanted to play the hole.

Knox opted not to, while Grace carded a birdie to finish on 12 under and Kisner had a par.

Northern Ireland's Rory McIlroy is eight under after a four-under 68.

Russell Knox walks down the 18th fairway in the fading light at the Sheshan International course

Too dark to play on

With Knox choosing not to finish in the dark, he will have to return on Sunday to play the par-five 18th.

"I played beautifully the first 12 or 13 holes and then I started to limp in a little bit so I decided not to play the last hole because it was awfully dark," said Knox, from Inverness.

"Branden and Kevin wanted to get done. It was into the wind and I was like, maybe I'll just wait until the morning and see if I can catch it downwind or no wind.

"I was happy with my decision. My caddie didn't want me to play the last.

"I'm going to have to wake up a lot earlier, starting at 7.45 and I won't tee off again until probably 10.45. It's going to take the best round of my life, so I'm going to have to go for it."

Spieth returns to form

Spieth, playing in his first tournament for two weeks, showed signs of rustiness as he shot 68 and 72 in his first two rounds but was close to his best in his third.

"This will be the first and only time I would say this, but I was not expecting to be in this position come Sunday when the week started," said the American, who needs to finish in the top 13 to reclaim the world number one ranking from Jason Day, who is absent as his wife is due to give birth to their second child.

"I've struggled to shoot lower than two or three under on this golf course in the past couple years, but Saturday was the day to do it with ball in hand, very little wind and some gettable pins.

"I missed four putts inside eight feet - I'm not going to complain about the round but I felt like the way I played could have been 10 or 11 under, for sure."