A late equalizer from Toche denied the north London outfit all three points in a game that never saw the team's true quality
Andre Villas-Boas' side was superior for the majority of the game, without ever reaching top gear and looked to have the game sewn up after Dawson nodded a Tom Huddlestone free kick past Orestis Karnezis. But the hosts awoke from their slumber and Toche slid home an equalizer after a sublime pass from Giourkas Seitaridis, leaving Spurs with two points from their opening two games.
Tottenham saw a claim for a penalty denied inside the first few minutes as Steven Caulker's downward header appeared to hit an arm but referee Florian Meyer deemed it accidental despite the away team's protestations.
In a largely empty Olympic Stadium, Tottenham looked to control the opening stages by retaining possession and probing the Panathinaikos defense for openings.
But it was the hosts who created the first notable opportunity as Stergos Marinos sent a rangy diagonal pass to the overlapping Seitaridis on the right side. The fullback found his way behind the Spurs defense and sent a dangerous cross in towards the lone frontman Toche but Hugo Lloris, given a start ahead of Brad Friedel, kept his concentration to claim the cross.
Aside from a later dropped cross by Lloris, that was as close as the hosts came to threatening the Tottenham goal as the Premier League side made its territorial dominance count.
Though the passing in midfield was at times sloppy, Aaron Lennon and Gareth Bale tested Orestis Karnezis with 20-yard shots, while Jermain Defoe fired a cross-cum-shot from the left that was unfortunate to elude the onrushing Clint Dempsey.
Yet, with 10 minutes until halftime Tottenham took the lead. Dawson, who was recalled and made captain for the night, marked the occasion by beating his marker at the near post to flick Huddlestone's inswinging free kick into the far corner.
Huddlestone, who was also given a rare start by Villas-Boas, almost closed the opening 45 with a fine half-volley from Defoe's layoff, only ruing Karnezis' alert diving stop.
Though it was a half of few chances, Spurs made their dominance count against a flat and insipid Panathinaikos and Jesualdo Ferreira understandably changed things at halftime, introducing Ibrahim Sissoko for Marinos.
The hosts looked more vibrant in the opening stages of the second half and certainly gave their vocal support a worthy dose of effort, but they were nearly two down on the 55th minute. Defoe latched onto a well-weighted through ball but although his first and second touches propeled him clear of the Panathinaikos defense, his third was a wild, blazed effort over the crossbar.
At the other end Quincy Owusu-Abeyie – a former Arsenal forward – looked the likeliest source of an equalizer and indeed, his clipped through ball to Lazaros Christodoulopoulos saw his teammate head against the post from six yards, albeit with the linesman's flag raised.
Tottenham was certainly not at its maximum and although Defoe saw a deflected effort from the edge of the box fizz just wide of goal, Panathinaikos pulled level with 14 minutes to play.
Greece international Seitaridis had pushed up into the Spurs half and with both Tottenham center backs too square, fed a lovely curved pass outside Caulker to Toche who had broken clear of Dawson. His first-time finish was steered just past Lloris and in off the far post, pulling the hosts level.
Villas-Boas, understandably frustrated, scampered up and down the touchline barking orders to his side as they looked to regain the lead but in truth, the mentality of the game had changed with the Greek side's equalizer.
A flurry of activity in the box in the final stages almost saw Ferreira's team snatch a late winner as substitute Charalampos Mavrias volleyed at goal but some stout defending saw Tottenham avert danger.
As the final whistle blew and the two former Porto coaches embraced, Villas-Boas' smile hid genuine disappointment. This was a game Spurs will view as two points dropped, particularly given the mediocre nature of their hosts' play. With just two points from six, the north Londoners will need to take a maximum haul against Maribor in their next two Europa League games.