Messi now stands alone as the only player to have scored a hat-trick four times in the tournament.
Barcelona: Lionel Messi marked his 80th Champions League match with a hat trick on Wednesday as Barcelona began their campaign in Group H with a 4-0 rout of Ajax.
The Argentina forward opened the scoring at Camp Nou Stadium with a free kick in the 22nd minute, doubled the hosts' advantage in the 55th on the break and, after Gerard Pique's 69th-minute goal, added another 15 minutes from fulltime. The goals took his cumulative tally in the competition to 62 - nine short of Raul Gonzalez's all-time record of 71 goals in 144 appearances.
Messi now stands alone as the only player to have scored a hat trick four times in the tournament.
"From (Frank) Rijkaard until now, the coaches that have come through here, every two or three games they have talked about how surprised they are by him, and I am just one more," said Barcelona coach Gerardo Martino, who will travel to his native Argentina following the death of his father on Tuesday.
Despite some lethargic moments late in the first half, Barcelona eased to the win thanks to Messi's goals and the team's near complete control of possession.
When Ajax did manage to create a scoring opportunity, Valdes was there to keep a clean sheet.
"As the game went on we adapted better as we figured out what to do," said Messi. "We couldn't put pressure on them at the beginning because they read the match perfectly."
AC Milan beat Celtic 2-0 in the night's other Group H game.
True to both teams' well-established playing styles, Barcelona and Ajax kept the ball on the turf. While Ajax was limited to former Barcelona forward Bojan Krkic's sprints down the left side, Barcelona soon focused on Neymar cutting in from the left flank.
But it fell to Messi to get the hosts going after he was fouled while dribbling across the edge of the area following a neat passing combination with Dani Alves.
From that prime spot, Messi sent a left-foot shot off the left post, with the ball beating outstretched goalkeeper Kenneth Vermeer before ricocheting into the far side of the net.
"We know that Messi can always score, and he did," said Ajax coach Frank de Boer, a former Barcelona defender. "His free kick was very good, very fast.
"I can't be happy. When you allow four goals you can't be. But I saw moments that we can build on for the games ahead."
Ricardo van Rhijn almost answered for Ajax in the 31st when Bojan picked him out with a cross, only for Valdes to smother his header.
The home crowd became nervous near the end of the first half, and Barcelona apparently took note by showing the defensive pressure Martino had said was his top priority to restore after the break.
The increased intensity paid off when Barcelona recovered the ball and Sergio Busquets spotted Messi running unmarked down the right side. Messi took his pass, cut back to bring Stefano Denswil to the ground and used his left foot to score.
Neymar, in his European debut, set up Gerard Pique to add Barcelona's third goal with a long cross.
Ajax lost possession near its area and Xavi Hernandez laid the ball off for Messi to take his time before driving it between a pair of defenders and into the corner of the net for his third goal.
Valdes had his moment of glory one minute later in the 76th when he blocked Kolbeinn Sigthorsson's penalty after Javier Mascherano fouled Thulani Serero in the box.
"We played a better second half," said Martino. "We were more comfortable than in the first and took control of the game. It was a good performance, not as brilliant as the 4-0 looks, but we won it fairly.
"Barcelona is full of individual talents. Today we can talk about Messi and Valdes, another day Xavi or Neymar. It is normal that one of them rises to the occasion."
Ajax's defeat was its ninth consecutive loss to a Spanish opponent. Ajax's last victory in Spain dates back even farther to the 1996-97 season when De Boer helped the Dutch team win at Atletico Madrid.
The two four-time champions had never met before in Europe's top-tier competition. Even so, fewer teams from different countries have stronger ties.
Dutch great Johan Cruyff led Ajax to three straight European titles from 1971-73 as a player before moving to Barcelona, where he would later return as a coach to guide it to its first European title in 1992.