Safin was unable to defend his Aussie Open title in January

Safin, playing for the first time since last August, overcame a shaky start to overpower his fellow Russian.

There was also a win for Roger Federer, who beat Swiss compatriot Stanislas Wawrinka 7-6 6-3 in his first match since winning the Australian Open.

Spain's Rafael Nadal beat Paul-Henri Mathieu 6-7 6-1 6-2 to reach round two.

Safin, who has slipped to 53 in the world rankings, will face Olivier Rochus in the second round after what he himself described as a surprise win over Davydenko.

I still have to climb some mountains Marat Safin

"I thought I had no chance when I saw the draw," said the former US and Australian open champion.

"Nikolay has been playing very well for 18 months, and at the start I couldn't really think I would make a set.

"I thought I would come out and play a few games - I didn't expect to win the match. I was still a little bit scared.

Fantastic for tennis now that Safin's back! From Mr I Have your say on Five Live

"There were some balls I didn't want to run for, and some movements were hard to make.

"I still have a little bit of pain but it's not the same pain as it used to be and I can move without any problems.

"But I think it was harder psychologically than physically, and I am surprised I won. He is a good player to beat. But I still have to climb some mountains."

Top seed Federer was made to work hard for his victory against Wawrinka, who rallied well, made few unforced errors and changed the pace to good effect.

After Federer had won the first set 7-3 in the tiebreak, seven of the nine games went against serve in the second.

"I thought my game was coming and going," said Federer.

"My serve wasn't that great in the beginning and then I really got a high percentage going and then it left me again."