Ireland's Shane Lowry is one shot off the lead at the BMW PGA Championship after a strong back nine pushed him in contention at Wentworth.
Lowry hit a hat-trick of birdies from the 12th to leave him right in the hunt and although his charge was halted by a bogey on the 15th, he followed that up with birdies on the 16th and 17th, leaving him on -5.
Lowry came agonisingly close to holing his chip shot on the 18th after flying the green, but was happy to sign for an opening 67.
"My iron play feels good and I drove it lovely and holed a few putts," said Lowry, who has missed the cut in three of his last four starts.
"That's probably the difference between shooting the scores I have been recently and today."
England's Tyrrell Hatton took route 66 to set the clubhouse target in the tournament which inspired him to become a professional.
Hatton carded an eagle, five birdies and a solitary bogey at Wentworth to finish six under par.
Playing alongside Hatton, former Masters champion Patrick Reed had held the lead following four birdies in succession around the turn, but eventually signed for a 70 after dropping a shot on the fifth and making a double bogey on his final hole after pulling his approach into the water.
Padraig Harrington maintained his recent good form by posting a level-par 72 in his opening round, while Graeme McDowell is a shot further back following his one over round.
Hatton grew up not far from Wentworth and often came to one of the European Tour's flagship events as a spectator, while he went into the final round in 2016 a shot off the lead before finishing seventh.
"I've been walking around here from the age of five so I feel pretty comfortable on the golf course," Hatton said. "I've been round it so many times it almost has that home-course feel.
"To lift the trophy here is definitely a goal of mine and hopefully I can play well the next few days and give myself the chance to do that. That would be very special."
Hatton, who won his fourth European Tour title in a six-man, floodlit play-off in the Turkish Airlines Open last November, underwent wrist surgery at the end of the season and started 2020 in superb style with a first PGA Tour title in the Arnold Palmer Invitational.
"It's nice to be pain-free after two and a half years," the 28-year-old added. "This year I've also been in the gym quite a bit and it's nice to have had the results we've had so far."
Rai finished runner-up in the Irish Open a fortnight ago and followed that with victory in the ASI Scottish Open on Sunday, defeating Tommy Fleetwood in a play-off.
"There wasn't much of a celebration," the 25-year-old from Wolverhampton said following his bogey-free 68.
"We drove back straight away after the Scottish Open and it was quite a long drive back home.
"I did spend Sunday night at home with my family, so I did get to see them. It was just nice to share a few moments without really having to celebrate, but maybe in a couple weeks' time."