Shortly after the World Cup, India toured Bangladesh for two Test matches and three ODIs. In the second Test, which Bangladesh lost by an innings and 239 runs, Ashraful scored the fastest half-century in Test cricket in terms of time (taking 27 minutes) and equal second-fastest when measured in balls faced (scored off 26 balls). Aside from the 67 he managed in one of the fastest half-centuries in Test cricket, Ashraful managed just five more runs in the series; in two ODIs, he scored 41 runs. After defeats in both series, Habibul Bashar stepped down from Bangladesh's one day captaincy; Mohammad Ashraful was appointed the team captain in all forms of cricket on 2 June 2007. At the time, he had played 35 Test and 101 ODIs and had some experience of captaincy at domestic level. Aged 22, he was the second-youngest international captain
Ashraful and Mortaza took on these roles from the start of the Sri Lanka tour in June 2007. Whatmore had declined to extend his contract and Shaun Williams took over as coach on a temporary basis. Bangladesh lost all three Tests by an innings; in a series in which his teams batsmen struggled – in the second Test they registered their lowest scored in an innings (62) – Ashraful scored the most runs for Bangladesh with 218 at an average of 43. In the second Test Ashraful combined with wicketkeeper Mushfiqur Rahim to score 191 for the sixth wicket, establishing a record for Bangladesh, and Ashraful scored 129 not out. Bangladesh also lost the three-match ODI series that followed 3–0. In September 2007 South Africa hosted the ICC World Twenty20. Victory against West Indies in the first round was enough to ensure Bangladesh's progression to the second round, although it was the only one of their five matches they won. In the match against West Indies, Ashraful scored a record-breaking half-century, coming off just 20 deliveries it was at the time the fastest T20I half-century in terms of balls faced; he held onto the record for six days before Yuvraj Singh claimed it in a match against England (his 50 took just 12 balls).