Baltacha looks in good form but tougher tests await Britain
Britain's Fed Cup team saw off Bosnia-Hercegovina 3-0 as their bid for promotion began in style in Portugal.
Katie O'Brien secured an easy 6-2 6-0 win over Ema Burgic, while British number one Elena Baltacha beat world number 387 Sandra Martinovic 6-1 6-1.
Baltacha then joined Sarah Borwell in the doubles to secure the whitewash.
Britain also play Austria and Belarus, with each group winner making the play-off on Saturday. April's World Group II play-offs await the two winning teams.
Within Group I, Europe/Africa, there are 16 nations in four pools with Bulgaria, Israel, Netherlands and Slovenia in group A, and Croatia, Portugal, Romania and Switzerland making up group B.
Denmark, Hungary, Latvia, Sweden are in group C with Britain in group D.
Baltacha, fresh from her impressive run in the Australian Open where she lost in the third round to Dinara Safina, said: "I think the most important thing was that I got a win.
"I think I played really well in patches and in patches not great, I don't think I've actually hit a forehand into the side fence before!"
The world number 83 rarely looked back after breaking Martinovic in the very first game. Despite dropping the first game of the second set, Baltacha went on to wrap up a comfortable victory.
The win followed O'Brien's fine start to the day in Lisbon with the Yorkshire-born player having few problems against Burgic.
"I think it was all about me being solid and making her move and that's what I did really. I served quite well as well which I was pleased with," the 23-year-old said.
Borwell and Baltacha dispatched the Bosnian doubles pair 6-3 6-2 to complete a good day for the Britons, although the Bosnians are regarded as the weakest team in the group.
Greater challenges lie ahead for the British team, that also includes Anne Keothavong returning to action after injuring a knee in July.
The Fed Cup format features two singles matches followed by one doubles encounter.
GB captain Nigel Sears said: "I'm very pleased. Even though they were the weakest team, the girls couldn't have done a better job.
"They were very professional, and pulled off a clean, decisive win. The rest of the week is only going to get tougher, but we're up for the challenge."
Their progression will depend on them finishing top of their four-team group and will have to face the might of Belarus, who are led by world number six Victoria Azarenka, on Friday.
The British women play their second match against the Austrians on Thursday.