Northern Ireland's Rory McIlroy made a really poor start on day one of the final major of the season - the USPGA Championship - with an opening bogey and then a double bogey on the 489-yard fourth.
Fellow Ulsterman and US Open champion Graeme McDowell bogeyed the short third.
Montgomerie was one over as well after dropping shots on the 16th and 17th, but Ireland's Shane Lowry birdied the 11th and 13th to be two under and in a tie for ninth.
Bad visibility delayed the start of the USPGA Championship for over three hours at Whistling Straits in Wisconsin.
When conditions eventually cleared beside Lake Michigan, Tiger Woods emerged from the fog to give his battered confidence a much-needed boost.
The world number one - a shocking joint 78th out of 80 in last week's world championship - scored a one-under-par 71.
It left him only three behind early pacesetters Bubba Watson and Italian Francesco Molinari.
Woods, needing a top-15 finish to have a chance of qualifying automatically for the Ryder Cup, birdied three of his first four holes and shared the lead at that point.
Dropping back to level par with bogeys on the 15th - his sixth - the long second and short seventh was a big disappointment, but he raised his morale again with a closing birdie.
That left him feeling far better about things than Padraig Harrington, who looks likely now to require one of Colin Montgomerie's three wild cards after managing only a three-over 75.
"I was very confident going out, but was a little bit too aggressive," said the Dubliner, who now concedes that in terms of the Ryder Cup he made some mistakes with his schedule earlier in the season.
"But I'm still trying to win the tournament. Eight under won here last time (that was Vijay Singh in 2004) and I don't see why it won't be again - but the cut will be an issue tomorrow."
Harrington's biggest error came on the short 17th, his eighth, where he pulled a four-iron onto the rocks by the water and double-bogeyed.
© Press Association