Gonzalo Castro's fortuitous goal ensured Borussia Dortmund remained unbeaten under Thomas Tuchel with a 1-1 draw at PAOK in the Europa League.

The midfielder netted with an attempted pass in the 72nd minute to earn a valuable Group C point, although it was no less than the Germans deserved for a dominant display.

Dortmund was looking to build upon a good start to its continental campaign in Greece, having enjoyed a 2-1 home win over Krasnodar in their opening fixture.

But a failure to take a series of opportunities in the early part of the clash came back to haunt the Bundesliga outfit as Robert Mak's emphatic finish put the host ahead 11 minutes before half-time.

Dortmund continued to dominate thereafter, however, and finally grabbed a deserved goal through Castro's moment of luck.

It continued to press forward in search of a winner and, while that did not come, Tuchel will doubtless be delighted not to head into the weekend's crucial clash with Bayern Munich on the back of a loss.

While Dortmund headed into this clash without a loss this season, it had drawn its two most recent fixtures after 11 successive wins in all competitions.

And Tuchel's men began the game like a team determined to ensure that did not happen again, with Jonas Hofmann hitting a volley narrowly over the crossbar.

The host was in a rich vein of form of its own having gone four games without a reverse, yet Dortmund continued to look the more threatening side as Sven Bender headed just wide after meeting Adnan Januzaj's corner.

That proved the first of several good chances in the early part of the opening half, with the best falling to Castro.

The midfielder played a fine one-two with Januzaj, only to see his effort denied by the legs of Robin Olsen.

Yet an opener remained elusive, with the visitor's frustration reaching boiling point when Hofmann fired a lovely low centre across the six-yard box that Marco Reus agonisingly failed to connect with.

Such annoyance paled in comparison to that felt when PAOK took the lead against the run of play in the 34th minute.

Erik Sabo played a delicious chipped pass over the top of the defence that Mak ran on to before hammering home a stunning strike off the underside of the crossbar.

The early stages of the second period continued along the same pattern of Dortmund dominance with little reward.

But its opponent continued to look a threat on the counter-attack, illustrated by Dimitar Berbatov only just missing the target with an audacious 30-yard lob.

It appeared Dortmund's endeavour would continue to bring little reward when Olsen denied Januzaj's free-kick.

Yet the goalkeeper's good work was undermined by an awful error moments later as, anticipating a touch from Reus, he was left helpless as Castro's chipped pass rolled beyond him into the corner.

That seemed to spur PAOK into life, and they almost grabbed a second in similar fashion when Roman Weidenfeller produced a diving stop to turn Jairo's cross around the post.

The Greeks were fortunate just to secure a draw, though, as Olsen's brilliant reactionary save denied an own goal before Park Joo-ho's driven effort flew inches wide.