Somdev breezes past his Czech opponent in only 69 minutes
Former India Davis Cupper Prakash Amritraj, who is now ranked 515th in the World, also won his match but in a contrasting style winning 6-7 (4) 6-2 6-2 against Rufin Guillaume of France.
Somdev, who has gone through a rough patch after returning from injury as his ATP ranking has slipped to 663 from top-100 rank a couple of years back.
On paper, Somdev was no match for his 106th ranked Czech opponent but India's top singles player proved his fitness which is a positive sign ahead of country's Davis Cup tie against South Korea in Delhi.
Once he broke Hajek in the very first game of the match, he grew in confidence and then in his first service game fired three aces to rattle his opponent.
Steadily, he went about his task and upped the ante and got better with each service game. He broke Hajek in the ninth game for the lead.
Devvarman seemed to have prepared well to take on the load and equipped with booming forehand drives. The Indian, who served seven aces in all, saved two of three break points in each set.
"It's my first match of the year and it feels great to have won it. It is always a pleasure playing in Chennai, the crowd support helped me immensely," Somdev said after the match.
"Coming back from injury after so many months, to win my first match of the season is a wonderful feeling. The next match is going to be tough since I'm playing a seeded player, but I'm feeling good and will go out there and do my best."
Devvarman plays world No 6 and top seed Tomas Berdych in the next round and it will take a Herculean effort from the Indian to win that encounter.
It was a creditable win for Prakash also, who is on his ninth visit to the tournament, and in all his first round wins he had got the better of higher seeds.
Now, Prakash plays eighth seeded Go Soeda of Japan in the second round.
In the other four matches, Matthias Bachinger (ranked 123) of Germany brought about
the first major upset of the tournament when he put paid to the aspirations of seventh seeded Lu Yen-Hsun 6-4, 3-6, 6-4 in 128 minutes.
Matthias broke Lu in the 10th game of the first set and Lu returned the favour in the first and ninth games of second set to the decider.
In the third game, Lu was in his elements and two points via ace only to be broken under pressure by the German. Matthias maintained the tempo to break Lu in the fifth game to win the set and the match.
The day proved to be a lucky day for the Germans, as Cedric Marcel Stebe, a qualifier ranked 171 defeated Ignor Sijsling of Netherlands in straight sets of 6-4, 6-4 in 84 minutes.
In yet another tie, fifth seeded Benoit Paire of France lived up to expectations against Flavio Cipolla of Italy. 23 year-old Benoit won the match 6-3, 6-4, while Spaniard Roberto Bautista Agut defeated Blaz Kavcic (Slo) 7-6, 6-2.