WARSAW (Reuters) - The Czech Republic were level at 0-0 with Portugal who came closest to scoring when Ronaldo hit the post after a fine piece of skill at the end of the opening 45 minutes in the first Euro 2012 quarter-final on Thursday.

Both sides enjoyed bright moments, with the Czechs prompted by the lively Petr Jiracek and Portugal looking to release their dangerous captain Ronaldo at every opportunity.

The winger failed to connect cleanly with an overhead kick to the delight of the Czech fans and fired a powerful 35-metre free kick well wide but almost scored after turning brilliantly before planting a firm shot against the post from a tight angle.

Nani and Miguel Veloso were booked for over-zealous tackles as tempers flared in a humid atmosphere under the closed roof at the National Stadium and the Portuguese suffered another blow when striker Helder Postiga was forced off with an injury.