England skipper Kevin Pietersen said he was not surprised by the series defeat to India, saying the hosts are a formidable unit.

Pietersen said though the defeat hurts, it is not a shock given India's stunning performances in the recent past.

Pietersen referred to India's 2-0 Test series win against world champions Australia and said his team lost to a formidable side.

"India is playing fantastic cricket at the moment. It was a learning curve for the youngsters and also the guys who have been around. It's never nice to lose a series and we are now 4-0 down in the series. But it was against a side which has beaten the mighty Australia and now England," Pietersen said.

Trailing the seven-match series 0-4 and facing a possible whitewash, Pietersen said England attack lost its firepower in India's placid tracks.

According to him, the Indians are generally vulnerable to swing and bounce but the tracks here were quite unresponsive.

"It has been a totally different ball game here," Pietersen rued.

The England captain, meanwhile, was highly impressed by the Team India vice captain and said, "Sehwag is great to watch."