Bangladesh's spinners struck twice late on the fourth day yesterday to keep the upper hand created by skipper Mahmudullah Riyad's long-awaited second Test hundred in the hosts' quest for a series-saving win in the second Test against Zimbabwe at the Sher-e-Bangla National Stadium in Mirpur.

Over the tea break, Bangladesh declared their second innings on 224 for six and set a huge target of 443 runs for Zimbabwe, who ended the day on 76 for two. The visitors, who have only ever won two away series in their Test history, need to score another 367 runs or bat out three sessions on today's final day to draw the match and win the series on the back of their 171-run win in the first Test.

After a good start provided by a 68-run opening stand between skipper Hamilton Masakadza and Brian Chari, Zimbabwe ended up losing two wickets in the final hour.

Mahmudullah was unbeaten on 101, which came off 122 deliveries with two sixes and four boundaries while Mehedi Hasan Miraz was unbeaten on 27.

The big question before play started was about whether Bangladesh, ahead by 218 runs in the first innings, would ask Zimbabwe to follow on or choose to set a target in order to make the visitors bat last on a pitch that would offer spinners more assistance on the last day.

According to Mehedi, who spoke after the day's play, Bangladesh took the safe route of posting a target of over 400 and avoid the pressure of batting in the fourth innings of the Test.

However, it was the worst possible start to their second innings with the top order once again failing as Bangladesh were struggling on 25 for four within the first hour.

Imrul Kayes played a rash shot away from his body off a short and wide delivery from pacer Kyle Jarvis and handed a catch at deep point, extending his poor run in the longest format to a 20th innings without a fifty.

Soon, fellow opener Liton Das was bowled by a brilliant Jarvis delivery which shaped away at the last moment.

First-innings centurion Mominul Haque edged a Donald Tiripano length delivery which he could have easily let go and then the seamer had first-innings double centurion Mushfiqur Rahim caught at deep square leg off an uppish pull.

Mahmudullah and debutant Mohammad Mithun, who was dismissed for a duck in the first dig, added 118 runs for the fifth wicket during which the latter registered his maiden fifty. Mahmudullah remained positive throughout the innings, which suited his style as seen in a much more successful limited-overs career. When Mithun was dismissed for 67, Bangladesh had already taken the lead past 300 runs.

Ariful Haque departed cheaply and Riyad inched towards his much-needed hundred with Mehedi for company and celebrated the feat in style.

He reached the mark, his first after a maiden century in Hamilton in February 2010, at the stroke of tea and the declaration came from the Tigers. It was the second time that Bangladesh declared both innings of a Test match after they had done so against West Indies in 2011 in Chattogram.

With a huge task at hand, Zimbabwe started the second innings well but skipper Masakadza was lucky to be dropped on five by Mehedi at second slip to deny debutant pacer Khaled Ahmed his maiden Test wicket.

Masakadza and Chari's stand was going strong, but the former was caught at bat-pad off Mehedi in the 23rd over and Taijul Islam trapped Chari leg before on 43 three overs and two runs later.