Halle Westfalen - Roger Federer began his last week of pre-Wimbledon competition with a 6-3, 6-4 defeat of Slovene Aljaz Bedene on Tuesday to reach the second round of the ATP Halle grass event.

The world number one needs to lift a record 10th title here on Sunday in order to remain at the summit of the rankings and assure himself the top seeding at Wimbledon starting a week from Monday.

"I got out of the box well, I felt good right away," Federer said. "This is an easier court to play than last week in Stuttgart. 

"The ball bounces up higher into my strike zone. I was connecting well on returns and I could read his serve.

"I played a solid first set once I figured out how to break him. In the second I was able to hold all of my serves. 

"For a first round and without much play on this court, It was fine, I'm very happy." 

Federer's straightforward victory in 71 minutes marked his 17th straight on the grass dating to June, 2017, when he lost in Stuttgart to Tommy Haas. 

The Halle defending champion, who has a laneway leading to the stadium named in his honour, has won exactly half of his 18 grass trophies at the wooded north German venue. 

Federer took back the top ranking from Rafael Nadal for the second time this season last week in Stuttgart as he returned to competition for the first time in three months after avoiding the clay season to prepare fully for the grass. 

The 36-year-old Swiss got off to an early break in the opening set against the 72nd-ranked Bedene, who briefly played for Britain. 

The top seed swept up the set and finished off the win after breaking for 5-4 in the second set. The Swiss delivered a one-two finishing punch of backhand down the line and forehand winner to advance with ease. 

He fired seven aces and never faced a break point; he next plays Benoit Paire, who defeated American Steve Johnson 7-5, 7-6 (7/5). 

Home fans experienced disappointment as second seed Alexander Zverev fell easily to Croatian Borna Coric 6-1, 6-4, with the German going down in less than 90 minutes on four breaks of serve. 

Zverev, the third seed, had lost the last two finals here, going down to Federer a year ago and exiting at the hands of compatriot Florian Meyer in 2016. 

Zverev had complained about being worn down at the French Open and he won three five-set matches in succession before losing to Dominic Thiem in the quarter-finals. 

A week of rest and a light grass training schedule were apparently not enough to revitalise the world number three.  

Home fans were pleased, though, as Philipp Kohlschreiber advanced 4-6, 6-3, 2-1, with Hungarian opponent Marton Fucsovics unable to continue after hurting his left thigh in a fall on the grass.

Kohlschreiber, who lost in last week's Stuttgart first round, was more pleased with his performance here. 

"Today was definitely an improvement," the German said. "The quality was higher and I felt better on court. 

"It's a pity that the match ended as it did. It was a tough fight, I wish him a good recovery as soon as possible." 

Kohlschreiber was joined in the second round by compatriot Florian Mayer, who upset last weekend's champion in the Netherlands Richard Gasquet, the eighth seed, 6-2, 6-2. 

Greek Stefanos Tsitsipas stepped onto the grass and emerged with a defeat of Frenchman Lucas Pouille 6-2, 7-6 (7/3).  

Russian Karen Khachanov put out Mischa Zverev 7-6 (7/5), 6-3 while Australian Matt Ebden overwhelmed Tunisia's Malek Jaziri  6-0, 7-6 (7/2).