Bangladesh made a flying start to the World Cup with a 21-run win over South Africa © AFP

Bangladesh captain Mashrafe Mortaza believes he and his players don't have to be 'very excited' about the way they've begun their World Cup 2019 campaign, and called for his players to remain calm as matches come thick and fast in the lengthy group stage.

Bangladesh shattered all doubts surrounding their batting abilities by piling on 330 runs at the Oval and then caught South Africa 21 runs short to begin with a memorable victory and condemn their opponents to their second defeat on the bounce.

"One other thing is that, it's very important for our players to stay calm. We have just won one match, there are eight more to go. This win doesn't take us anywhere in this tournament now. So, I don't think we have to be very excited right now. There is still a long way to go," Mortaza said.

Despite downing a superior ODI side on paper, Mortaza felt it was already time for him and his troops to train all their focus and energies on their next fixture - against New Zealand on Wednesday at the Oval.

"I will say that we don't have to look that far [semis] yet. It's just one match, we were focused today. This match is over and we should stop thinking about it," he said.

"We have to plan for our next match against New Zealand. And we have to make sure that we execute those plans. We should give more importance to that, I think. If we had lost today's match then I think it wouldn't have helped us. We won today, may be it will improve our confidence. But I think more challenges will come. May be more challenges are waiting for the batsmen in the next matches," he added.

Mortaza, however, praised his players for putting on a fearless brand of cricket. "Mainly we talked [about the game] yesterday. The thing that we discussed is that we have nothing to lose," Mortaza told reporters after their win against South Africa, adding that all he wanted was to fight till the last ball.

The big all-round performance has now given the World Cup a new lease of life after a couple of one-sided affairs early on, and more importantly, could alter the way other teams perceive Bangladesh as an opposition. They afterall, answered all their critics who questioned if their batsmen were capable of posting big scores in anticipation of a high-scoring World Cup. Mortaza though, is not seeing too much into the perception change, and warned his teammates that such a perfect performance may not be possible each time.

"It depends on how other teams are thinking about us. We are looking at every team as a big team and we will try to give our best," he said. "We have make sure that players don't get injured, if everyone stays fit as that would be good for us. May be this [the performance against SA] won't happen in every match, that's for sure. But if everyone gives their best we have the ability to do lot better,'' he said.

The edifice of Bangladesh's victory was built on the 142-run stand for the third wicket, which was characterised by risk-free cricket from Shakib Al Hasan (75 off 84) and Mushfiqur Rahim (78 off 80).

"It was good to see that they built the innings risk free. I think it's a message that they gave to themselves that in these type of wickets you don't have to take too many risks. If the wickets were slower, then maybe they had to take some risks," said Mashrafee.

"The main thing is that you have to spend time on the wicket, then playing becomes easier here. I hope our batsmen understood it very well, and I think the more time we spend on the crease, it will be easier for us to bat. So, I hope if we keep that in mind, next match will be easier for us," he said, adding that he was glad to see his punt of promoting Shakib at 3 worked.

"I think last year he started to bat at three, but unfortunately in the final, he got injured, and it takes around six months to come back. Once he's come back, a few matches he played at five. Again, we thought that [there was] no experience - he brought that experience and made sure that in the top order that he batted, he's more responsible and can take all the pressure, and deliver at his best," he added, referring to Shakib's match-winning knock.

"So that was the thought behind promoting him at three and he was spot on," he said.

Mortaza also revealed he was a firm believer of luck, and that his team needs it if they harbour dreams of advancing ahead in the tournament.

"If any other captain was in my place, may be he would have said it differently. But I believe in luck. Of course we do planning, every team does that. But planning doesn't always work, luck is also necessary. If we want to get the best result in this type of tournament, you will need the favor of luck all time,'' he said

"If you see today's match, among all the turning balls, the one that spun the most was the one that got Du Plessis's wicket. We didn't expect that ball will turn that much. So that's the thing, you have to have some luck. So, if we want to do well in this tournament we have to have some luck, only playing well isn't enough," he concluded.