Tiger Woods continued to lead the Open championship at St Andrews today - but Colin Montgomerie was also giving the home crowd something to cheer.

Woods watched as the morning starters were unable to dislodge him from the top of the leaderboard, starting his second round moments after Vijay Singh missed a birdie putt on the 18th to take the outright lead.

Singh had to settle for a 69 and six-under halfway total of 138, sharing the clubhouse lead with South African Trevor Immelman and American Brad Faxon.

Sergio Garcia was a shot behind after a birdie at the last to complete a second-round 70, alongside 45-year-old former Masters champion Fred Couples who was round in 71.

Woods, winner here in 2000 in a record total of 19 under par, then cruised to the turn in 33 courtesy of birdies at the third, fifth and ninth to lead at nine under, four clear of an impressive Montgomerie.

The Scot picked up birdies at the first - where he drove into the Swilcan Burn yesterday - and third, and then eagled the par-five fifth to delight his blonde wig-wearing fan club.

It was looking almost certain Jack Nicklaus' second round would be his last in a major championship however, the 65-year-old three over par after 12 holes with the cut predicted to fall at level par.

Playing partner Luke Donald recovered from a double bogey at the second to lie four under.

Earlier in the day Singh missed a hatful of birdie chances - "So many I'm not even going to count" - but the world number two added: "I'm kind of disappointed but happy with my position.

"I just could not get the right pace on the greens and left a lot of putts short. I had one pace set for yesterday but with the rain they have slowed up a little bit.

"I'm playing well and striking the ball well and I just have to be patient and wait until they start falling."

Ernie Els could also be forgiven for wondering what might have been after firing eight birdies in a second round 67 to lie three under par.

The world number three also carded three bogeys and could only manage pars on two reachable par fours. "I got off to a good start but still made a lot of mistakes," admitted Els.

"I made eight birdies because the flags are a little more accessible and I have to be happy with that after yesterday's 74."

Els went to the turn in 32 with five birdies and one bogey, and did well to escape with a par on the short ninth after driving into a bush just short of the green and taking a penalty drop.

Another birdie on the 10th was followed by a bogey on the 11th where he overshot the green, and a birdie chance on the 12th went begging when his drive caught a pot bunker short of the green.

"I didn't play the turn well yesterday and it was the same again today," added the South African, who also bogeyed the 13th.

The 35-year-old has been struggling with his putting in recent weeks and missed a good chance on the 17th before closing with a birdie on the last from 10 feet.

"It's very frustrating, especially when you feel you're playing well but can't seem to get a score on the board," he added.

"But today I started to make some more putts and I just have to be more patient."